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A Guide To The Study Of Fishes

David Starr Jordan

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A GUIDE TO THE STUDY OF FISHES

A GUIDE TO THE STUDY OF FISHES

BY DAVID STARR JORDAN President of Leland Stanford Junior University With Colored Frontispieces and 427 Illustrations IN TWO VOLUMES Vol I. "I am the wiser in respect to all knowledge and the better qualified for all fortunes for knowing that there is a minnow in that brook."— Thoreau NEW YORK HENRY HOLT AND COMPANY 1905 NEW YORK HENRY HOLT AND COMPANY 1905 Copyright, 1905 BY HENRY HOLT AND COMPANY Published March, 1905 To Theodore Gill, Ichthyologist, Philosopher, Critic, Master in Taxonomy, th

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PREFACE

PREFACE

This work treats of the fish from all the varied points of view of the different branches of the study of Ichthyology. In general all traits of the fish are discussed, those which the fish shares with other animals most briefly, those which relate to the evolution of the group and the divergence of its various classes and orders most fully. The extinct forms are restored to their place in the series and discussed along with those still extant. In general, the writer has drawn on his own experien

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ERRATA[1] VOL. I

ERRATA[1] VOL. I

[Pg x] [Pg xi] [1] For most of this list of errata I am indebted to the kindly interest of Dr. B. W. Evermann....

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CHAPTER I THE LIFE OF THE FISH

CHAPTER I THE LIFE OF THE FISH

A POPULAR ACCOUNT OF THE LIFE OF THE LONG-EARED SUNFISH, LEPOMIS MEGALOTIS What is a Fish? —A fish is a back-boned animal which lives in the water and cannot ever live very long anywhere else. Its ancestors have always dwelt in water, and most likely its descendents will forever follow their example. So, as the water is a region very different from the fields or the woods, a fish in form and structure must be quite unlike all the beasts and birds that walk or creep or fly above ground, breathing

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CHAPTER III THE DISSECTION OF THE FISH

CHAPTER III THE DISSECTION OF THE FISH

The Blue-green Sunfish. —The organs found in the abdominal cavity of the fish may be readily traced in a rapid dissection. Any of the bony fishes may be chosen, but for our purposes the sunfish will serve as well as any. The names and location of the principal organs are shown in the accompanying figure, from Kellogg's Zoology. It represents the blue-green sunfish, Apomotis cyanellus , from the Kansas River, but in these regards all the species of sunfishes are alike. We may first glance at the

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CHAPTER IX THE ORGANS OF REPRODUCTION

CHAPTER IX THE ORGANS OF REPRODUCTION

The Germ-cells. —In most fishes the germ-cells are produced in large sacs, ovaries or testes, arranged symmetrically one on either side of the posterior part of the abdominal cavity. The sexes are generally but not always similar externally, and may be distinguished on dissection by the difference between the sperm-cells and the ova. The ovary with its eggs is more yellow in color and the contained cells appear granular. The testes are whitish or pinkish, their secretion milk-like, and to the na

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CHAPTER XIII THE COLORS OF FISHES

CHAPTER XIII THE COLORS OF FISHES

Pigmentation . —The colors of fishes are in general produced by oil sacs or pigment cells beneath the epidermis or in some cases beneath the scales. Certain metallic shades, silvery blue or iridescent, are produced, not by actual pigment, but, as among insects, by the deflection of light from the polished skin or the striated surfaces of the scales. Certain fine striations give an iridescent appearance through the interference of light. The pigmentary colors may be divided into two general class

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CHAPTER XIX DISEASES OF FISHES

CHAPTER XIX DISEASES OF FISHES

Contagious Diseases. —As compared with other animals the fishes of the sea are subject to but few specific diseases. Those in fresh waters, being more isolated, are more frequently attacked by contagious maladies. Often these diseases are very destructive. In an "epidemic" in Lake Mendota, near Madison, Wis., Professor Stephen A. Forbes reports a death of 300 tons of fishes in the lake. I have seen similar conditions among the land-locked alewife in Cayuga and Seneca Lakes, the dead fishes being

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CHAPTER XX THE MYTHOLOGY OF FISHES

CHAPTER XX THE MYTHOLOGY OF FISHES

The Mermaid. —A word may be said of the fishes which have no existence in fact and yet appear in popular literature or in superstition. The mermaid, half woman and half fish, has been one of the most tenacious among these, and the manufacture of their dried bodies from the head, shoulders, and ribs of a monkey sealed to the body of a fish has long been a profitable industry in the Orient. The sea-lion, the dugong, and other marine mammals have been mistaken for mermaids, for their faces seen at

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CHAPTER XXIII THE COLLECTION OF FISHES

CHAPTER XXIII THE COLLECTION OF FISHES

How to Secure Fishes. —In collecting fishes three things are vitally necessary—a keen eye, some skill in adapting means to ends, and some willingness to take pains in the preservation of material. In coming into a new district the collector should try to preserve the first specimen of every species he sees. It may not come up again. He should watch carefully for specimens which look just a little different from their fellows, especially for those which are duller, less striking, or with lower fi

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CHAPTER XXIV THE EVOLUTION OF FISHES

CHAPTER XXIV THE EVOLUTION OF FISHES

The Geological Distribution of Fishes. —The oldest unquestioned remains of fishes have been very recently made known by Mr. Charles D. Walcott, from rocks of the Trenton period in the Ordovician or Lower Silurian. These are from Cañon City in Colorado. Among these is certainly a small Ostracophore ( Asteraspis desideratus ). With it are fragments ( Dictyorhabdus ) thought to be the back-bone of a Chimæra, but more likely, in Dean's view, the axis of a cephalopod, besides bony, wrinkled scales, r

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CHAPTER XXV THE PROTOCHORDATA

CHAPTER XXV THE PROTOCHORDATA

The Chordate Animals. —Referring to our metaphor of the tree with its twigs as used in the chapter on classification we find the fishes with the higher vertebrates as parts of a great branch from which the lower twigs have mostly perished. This great branch, phylum, or line of descent is known in zoology as Chordata , and the organisms associated with it or composing it are chordate animals. The chordate animals are those which at some stage of life possess a notochord or primitive dorsal cartil

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CHAPTER XXVI THE TUNICATES, OR ASCIDIANS

CHAPTER XXVI THE TUNICATES, OR ASCIDIANS

Structure of Tunicates. —One of the most singular groups of animals is that known as Ascidians, or Tunicates. It is one of the most clearly marked yet most heterogeneous of all the classes of animals, and in no other are the phenomena of degeneration so clearly shown. Among them is a great variety of form and habit. Some lie buried in sand; some fasten themselves to rocks; some are imbedded in great colonies in a gelatinous matrix produced from their own bodies, and some float freely in long cha

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CHAPTER XXVII THE LEPTOCARDII, OR LANCELETS

CHAPTER XXVII THE LEPTOCARDII, OR LANCELETS

The Lancelet. —The lancelet is a vertebrate reduced to its very lowest terms. The essential organs of vertebrate life are there, but each one in its simplest form unspecialized and with structure and function feebly differentiated. The skeleton consists of a cartilaginous notochord inclosed in a membranous sheath. There is no skull. No limbs, no conspicuous processes, and no vertebræ are present. The heart is simply a long contractile tube, hence the name Leptocardii (from λεπτός, slender; καρδί

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CHAPTER XXVIII THE CYCLOSTOMES, OR LAMPREYS

CHAPTER XXVIII THE CYCLOSTOMES, OR LAMPREYS

The Lampreys. —Passing upward from the lancelets and setting aside the descending series of Tunicates, we have a long step indeed to the next class of fish-like vertebrates. During the period this great gap represents in time we have the development of brain, skull, heart, and other differentiated organs replacing the simple structures found in the lancelet. The presence of brain without limbs and without coat-of-mail distinguishes the class of Cyclostomes , or lampreys (κυκλός, round; στόμα, mo

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CHAPTER XXIX THE CLASS ELASMOBRANCHII OR SHARK-LIKE FISHES

CHAPTER XXIX THE CLASS ELASMOBRANCHII OR SHARK-LIKE FISHES

The Sharks. —The gap between the lancelets and the lampreys is a very wide one. Assuming the primitive nature of both groups, this gap must represent the period necessary for the evolution of brain, skull, and elaborate sense organs. The interspace between the lampreys and the nearest fish-like forms which follow them in an ascending scale is not less remarkable. Between the lamprey and the shark we have the development of paired fins with their basal attachments of shoulder-girdle and pelvis, t

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ERRATA[1]Vol. II

ERRATA[1]Vol. II

The adoption of the Code of the International Congress of Zoology necessitates a few changes in generic names used in this book. 1 . For most of this list of errata I am indebted to the kindly interest of Dr. B. W. Evermann....

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CHAPTER ITHE GANOIDS

CHAPTER ITHE GANOIDS

Subclass Actinopteri. —In our glance over the taxonomy of the earlier Chordates, or fish-like vertebrates, we have detached from the main stem one after another a long series of archaic or primitive types. We have first set off those with rudimentary notochord, then those with retrogressive development who lose the notochord, then those without skull or brain, then those without limbs or lower jaw. The residue assume the fish-like form of body, but still show great differences among themselves.

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CHAPTER IITHE GANOIDS—Continued

CHAPTER IITHE GANOIDS—Continued

Classification of Ganoids. —The subdivision of the series of Ganoidei into orders offers great difficulty from the fact of the varying relationships of the members of the group and the fact that the great majority of the species are known only from broken skeletons preserved in the rocks. It is apparently easy to separate those with cartilaginous skeletons from those with these bones more or less ossified. It is also easy to separate those with bony scales or plates from those having the scales

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CHAPTER IIIISOSPONDYLI

CHAPTER IIIISOSPONDYLI

The Subclass Teleostei, or Bony Fishes. —The fishes which still remain for discussion constitute the great subclass or series of Teleostei ( τελεός , true; οστέον , bone), or bony fishes. They lack wholly or partly the Ganoid traits, or show them only in the embryo. The tail is slightly, if at all, heterocercal; the actinosts of the pectoral fins are few and large, rarely over five in number, except among the eels; the fulcra disappear; the air-bladder is no longer cellular, except in very rare

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CHAPTER IVSALMONIDÆ

CHAPTER IVSALMONIDÆ

The Salmon Family. —The series or suborder Salmonoidea , or allies of the salmon and trout, are characterized as a whole by the presence of the adipose fin, a structure also retained in Characins and catfishes, which have no evident affinity with the trout, and in the lantern-fishes, lizard-fishes, and trout-perches, in which the affinity is very remote. Probably these groups all have a common descent from some primitive fish having an adipose fin, or at least a fleshy fold on the back. Of all t

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CHAPTER VSALMONIDÆ—(Continued)

CHAPTER VSALMONIDÆ—(Continued)

Salmo , the Trout and Atlantic Salmon. —The genus Salmo comprises those forms of salmon which have been longest known. As in related genera, the mouth is large, and the jaws, palatines, and tongue are armed with strong teeth. The vomer is flat, its shaft not depressed below the level of the head or chevron (the anterior end). There are a few teeth on the chevron; and behind it, on the shaft, there is either a double series of teeth or an irregular single series. These teeth in the true salmon di

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CHAPTER VITHE GRAYLING AND THE SMELT

CHAPTER VITHE GRAYLING AND THE SMELT

The Grayling, or Thymallidæ. —The small family of Thymallidæ , or grayling, is composed of finely organized fishes allied to the trout, but differing in having the frontal bones meeting on the middle line of the skull, thus excluding the frontals from contact with the supraoccipital. The anterior half of the very high dorsal is made up of unbranched simple rays. There is but one genus, Thymallus , comprising very noble game-fishes characteristic of subarctic streams. Fig. 80. —Alaska Grayling, T

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CHAPTER VIITHE APODES, OR EEL-LIKE FISHES

CHAPTER VIITHE APODES, OR EEL-LIKE FISHES

The Eels. —We may here break the sequence from the Isospondyli to the other soft-rayed fishes, to interpolate a large group of uncertain origin, the series or subclass of eels. The mass of apodal or eel-like fishes has been usually regarded as constituting a single order, the Apodes ( ἄ , without; ποῦς , foot). The group as a whole is characterized by the almost universal separation of the shoulder-girdle from the skull, by the absence of the mesocoracoid arch on the shoulder-girdle, by the pres

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CHAPTER VIIISERIES OSTARIOPHYSI

CHAPTER VIIISERIES OSTARIOPHYSI

Ostariophysi. —A large group of orders, certainly of common descent, may be brought together under the general name of Ostariophysi ( ὀσταρίον , a small bone; θυσός , inflated). These are in many ways allied to the Isospondyli , but they have undergone great changes of structure, some of the species being highly specialized, others variously degenerate. A chief character is shared by all the species. The anterior vertebræ are enlarged, interlocked, considerably modified, and through them a serie

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CHAPTER IXTHE NEMATOGNATHI, OR CATFISHES

CHAPTER IXTHE NEMATOGNATHI, OR CATFISHES

The Nematognathi. —The Nematognathi ( νῆμα , thread; γνάθος , jaw), known collectively as catfishes, are recognized at once by the fact that the rudimentary and usually toothless maxillary is developed as the bony base of a long barbel or feeler. Usually other feelers are found around the head, suggesting the "smellers" of a cat. The body is never scaly, being either naked and smooth or else more or less completely mailed with bony plates which often resemble superficially those of a sturgeon. O

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CHAPTER XTHE SCYPHOPHORI, HAPLOMI, AND XENOMI

CHAPTER XTHE SCYPHOPHORI, HAPLOMI, AND XENOMI

Order Scyphophori. —The Scyphophori ( σκύφος , cup; φορέω , to bear) constitutes a small order which lies apparently between the Gymnonoti and the Isospondyli . Boulenger unites it with the Isospondyli . The species, about seventy-five in number, inhabit the rivers of Africa, where they are important as food-fishes. In all there is a deep cavity on each side of the cranium covered by a thin bony plate, the supertemporal bone. There is no symplectic bone, and the subopercle is very small or conce

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CHAPTER XIACANTHOPTERYGII; SYNENTOGNATHI

CHAPTER XIACANTHOPTERYGII; SYNENTOGNATHI

Order Acanthopterygii, the Spiny-rayed Fishes. —The most of the remaining bony fishes constitute a natural group for which the name Acanthopterygii ( ἄκανθα , spine; πτερύξ , πτερόν , fin or wing) may be used. This name is often written Actinopteri , a form equally correct and more euphonious and convenient. These fishes are characterized, with numerous exceptions, by the presence of fin spines, by the connection of the ventral fins with the shoulder-girdle, by the presence in general of more th

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CHAPTER XIIPERCESOCES AND RHEGNOPTERI

CHAPTER XIIPERCESOCES AND RHEGNOPTERI

Suborder Percesoces. —In the line of direct ascending transition from the Haplomi and Synentognathi , the pike and flying-fish, towards the typical perch-like forms, we find a number of families, perch-like in essential regards but having the ventral fins abdominal. These types, represented by the mullet, the silverside, and the barracuda, have been segregated by Cope as an order called Percesoces (Perca, perch; Esox, pike), a name which correctly describes their real affinities. In these typica

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CHAPTER XIIIPHTHINOBRANCHII: HEMIBRANCHII, LOPHOBRANCHII,AND HYPOSTOMIDES

CHAPTER XIIIPHTHINOBRANCHII: HEMIBRANCHII, LOPHOBRANCHII,AND HYPOSTOMIDES

Fig. 180. —Shoulder-girdle of a Stickleback, Gasterosteus aculeatus Linnæus. (After Parker.) Fig. 181. —Shoulder-girdle of Fistularia petimba Lacépède, showing greatly extended interclavicle, the surface ossified. Suborder Hemibranchii. —Still another transitional group, the Hemibranchii , is composed of spiny-rayed fishes with abdominal ventrals. In this suborder there are other points of divergence, though none of high importance. In these fishes the bones of the shoulder-girdle are somewhat d

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CHAPTER XIVSALMOPERCÆ AND OTHER TRANSITIONALGROUPS

CHAPTER XIVSALMOPERCÆ AND OTHER TRANSITIONALGROUPS

Suborder Salmopercæ, the Trout-perches: Percopsidæ. —More ancient than the Hemibranchii , and still more distinctly in the line of transition from soft-rayed to spiny-rayed fishes, is the small suborder of Salmopercæ . This is characterized by the presence of the adipose fin of the salmon, in connection with the mouth, scales, and fin-spines of a perch. The premaxillary forms the entire edge of the upper jaw, the maxillary being without teeth. The air-bladder retains a rudimentary duct. The bone

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CHAPTER XVBERYCOIDEI

CHAPTER XVBERYCOIDEI

The Berycoid Fishes. —We may place in a separate order a group of fishes, mostly spiny-rayed, which appeared earlier in geological time than any other of the spinous forms, and which in several ways represent the transition from the isospondylous fishes to those of the type of the mackerel and perch. In the berycoid fishes the ventral fins are always thoracic, the number of rays almost always greater than I, 5, and in all cases an orbitosphenoid bone is developed in connection with the septum be

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CHAPTER XVIPERCOMORPHI

CHAPTER XVIPERCOMORPHI

Suborder Percomorphi, the Mackerels and Perches. —We may place in a single suborder the various groups of fishes which cluster about the perches, and the mackerels. The group is not easily definable and may contain heterogeneous elements. We may, however, arrange in it, for our present purposes, those spiny-rayed fishes having the ventral fins thoracic, of one spine and five rays (the ventral fin occasionally wanting or defective, having a reduced number of rays), the lower pharyngeal bones sepa

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CHAPTER XVIICAVALLAS AND PAMPANOS

CHAPTER XVIICAVALLAS AND PAMPANOS

The Pampanos: Carangidæ. —We next take up the great family of Pampanos, Carangidæ , distinguished from the Scombridæ as a whole by the shorter, deeper body, the fewer and larger vertebræ, and by the loss of the provision for swift movement in the open sea characteristic of the mackerels and their immediate allies. A simple mark of the Carangidæ is the presence of two separate spines in front of the anal fin. These spines are joined to the fin in the young. All of the species undergo considerable

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CHAPTER XVIIIPERCOIDEA, OR PERCH-LIKE FISHES

CHAPTER XVIIIPERCOIDEA, OR PERCH-LIKE FISHES

Percoid Fishes. —We may now take up the long series of the Percoidea , the fishes built on the type of the perch or bass. This is a group of fishes of diverse habits and forms, but on the whole representing better than any other the typical Acanthopterygian fish. The group is incapable of concise definition, or, in general, of any definition at all; still, most of its members are definitely related to each other and bear in one way or another a resemblance to the typical form, the perch, or more

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CHAPTER XIXTHE BASS AND THEIR RELATIVES

CHAPTER XIXTHE BASS AND THEIR RELATIVES

The Cardinal-fishes. Apogonidæ. —The Apogonidæ or cardinal-fishes are perch-like fishes, mostly of small size, with two distinct short dorsal fins. They are found in the warm seas, and many of them enter rivers, some even inhabiting hot springs. Many of the shore species are bright red in color, usually with black stripes, bands, or spots. Still others, however, are olive or silvery, and a few in deeper water are violet-black. Fig. 252. —Cardinal-fish, Apogon retrosella Gill. Mazatlan. The speci

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CHAPTER XXTHE SURMULLETS, THE CROAKERS AND THEIRRELATIVES

CHAPTER XXTHE SURMULLETS, THE CROAKERS AND THEIRRELATIVES

Fig. 289. —Red Goatfish, or Salmonete, Pseudupeneus maculatus Bloch. Family Mullidæ (Surmullets.) The Surmullets, or Goatfishes: Mullidæ. —The Mullidæ (Surmullets) are shore-fishes of the warm seas, of moderate size, with small mouth, large scales, and possessing the notable character of two long, unbranched barbels of firm substance at the chin. The dorsal fins are short, well separated, the first of six to eight firm spines. There are two anal spines and the ventral fins, thoracic, are formed

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CHAPTER XXILABYRINTHICI AND HOLCONOTI

CHAPTER XXILABYRINTHICI AND HOLCONOTI

The Labyrinthine Fishes. —An offshoot of the Percomorphi is the group of Labyrinthici , composed of perch-like fishes which have a very peculiar structure to the pharyngeal bones and respiratory apparatus. This feature is thus described by Dr. Gill: "The upper elements of one of the pairs of gill-bearing arches are peculiarly modified. The elements in question (called branchihyal) of each side, instead of being straight and solid, as in most fishes, are excessively developed and provided with se

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CHAPTER XXIICHROMIDES AND PHARYNGOGNATHI

CHAPTER XXIICHROMIDES AND PHARYNGOGNATHI

Suborder Chromides. —The suborder Chromides contains spiny-rayed fishes similar to the perch-like forms in most regards, but strikingly distinguished by the complete union of the lower pharyngeal bones, as in the Holconoti and Pharyngognathi , and still more remarkably by the presence of but one nasal opening on each side. In all the perch-like fishes and in nearly all others there are two nasal openings or nostrils on each side, these two entering into the same nasal sac. In all the Chromides t

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CHAPTER XXIIITHE SQUAMIPINNES

CHAPTER XXIIITHE SQUAMIPINNES

Fig. 335. — Monodactylus argenteus (Linnæus). From Apia, Samoa. Family Scorpididæ . The Squamipinnes. —Very closely allied to the Percomorphi is the great group called Squamipinnes ( squama , scale; pinna , fin) by Cuvier and Epelasmia by Cope. With a general agreement with the Percomorphi , it is distinguished by the more or less complete soldering of the post-temporal with the cranium. In the more specialized forms we find also a soldering of the elements of the upper jaw, and a progressive re

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CHAPTER XXIVSERIES PLECTOGNATHI

CHAPTER XXIVSERIES PLECTOGNATHI

The Plectognaths. —Derived directly from the Acanthuridæ , from which they differ by progressive steps of degeneration, are the three suborders of Sclerodermi , Ostracodermi , and Gymnodontes , forming together the series or suborder of Plectognathi . As the members of this group differ from one another more widely than the highest or most generalized forms differ from the Acanthuridæ , we do not regard it as a distinct order. The forms included in it differ from the Acanthuridæ much as the swor

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CHAPTER XXVPAREIOPLITÆ, OR MAILED-CHEEK FISHES

CHAPTER XXVPAREIOPLITÆ, OR MAILED-CHEEK FISHES

The Mailed-cheek Fishes. —The vast group of Pareioplitæ ( Loricati ) or mailed-cheek fishes is characterized by the presence of a "bony stay" or backward-directed process from the third suborbital. This extends backward across the cheek toward the preopercle. In the most generalized forms this bony stay is small and hidden under the skin. In more specialized forms it grows larger, articulates with the preopercle, and becomes rough or spinous at its surface. Finally, it joins the other bones to f

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CHAPTER XXVIGOBIOIDEI, DISCOCEPHALI, AND TÆNIOSOMI

CHAPTER XXVIGOBIOIDEI, DISCOCEPHALI, AND TÆNIOSOMI

Suborder Gobioidei, the Gobies: Gobiidæ. —The great family of Gobiidæ , having no near relations among the spiny-rayed fishes, may be here treated as forming a distinct suborder. The chief characteristics of the family are the following: The ventral fins are thoracic in position, each having one spine and five soft rays, in some cases reduced to four, but never wanting. The ventral fins are inserted very close together, the inner rays the longest, and in most cases the two fins are completely jo

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CHAPTER XXVIISUBORDER HETEROSOMATA

CHAPTER XXVIISUBORDER HETEROSOMATA

The Flatfishes. —Perhaps the most remarkable offshoot from the order of spiny-rayed fishes is the great group of flounders and soles, called by Bonaparte Heterosomata ( ἔτερός , differing; σῶμα , body). The essential character of this group is found in the twisting of the anterior part of the cranium, an arrangement which brings both eyes on the same side of the head. This is accompanied by a great compression of the body, as a result of which the flounders swim horizontally or lie flat on the s

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CHAPTER XXVIIISUBORDER JUGULARES

CHAPTER XXVIIISUBORDER JUGULARES

The Jugular-fishes. —In all the families of spiny-rayed fishes, as ranged in order in the present work, from the Berycidæ to the Soleidæ , the ventrals are thoracic in position, the pelvis, if present, being joined to the shoulder-girdle behind the symphysis of the clavicles so that the ventral fin falls below or behind the pectoral fin. To this arrangement the families of Bembradidæ and Pinguipedidæ offer perhaps the only exceptions. In all the families which precede the Berycidæ in the linear

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CHAPTER XXIXTHE BLENNIES: BLENNIIDÆ

CHAPTER XXIXTHE BLENNIES: BLENNIIDÆ

Fig. 447. —Sarcastic Blenny, Neoclinus satiricus Girard. Monterey. The great family of blennies, Blenniidæ , contains a vast number of species with elongate body, numerous dorsal spines, without suborbital stay or sucking-disk, and the ventrals jugular, where present, and of one spine and less than five soft rays. Most of them are of small size, living about rocks on the sea-shores of all regions. In general they are active fishes, of handsome but dark coloration, and in the different parts of t

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CHAPTER XXXOPISTHOMI AND ANACANTHINI

CHAPTER XXXOPISTHOMI AND ANACANTHINI

Order Opisthomi. —The order Opisthomi ( ὄπισθη , behind; ὤμος , shoulder) is characterized by the general traits of the blennies and other elongate, spiny-rayed fishes, but the shoulder-girdle, as in the Apodes and the Heteromi , is inserted on the vertebral column well behind the skull. The single family, Mastacembelidæ , is composed of eel-shaped fishes with a large mouth and projecting lower jaw, inhabiting the waters of India, Africa, and the East Indies. They are small in size and of no eco

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CHAPTER XXXIORDER PEDICULATI: THE ANGLERS

CHAPTER XXXIORDER PEDICULATI: THE ANGLERS

The Angler-fishes. —The few remaining fishes possess also jugular ventral fins, but in other regards they show so many peculiarities of structure that we may well consider them as forming a distinct order, Pediculati ( pedicula , a foot-stalk), although the relation of these forms to the Batrachoididæ seems a very close one. The most salient character of the group is the reduction and backward insertion of the gill-opening, which is behind the pectoral fins, not in front of them as in all other

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