BY J. D. F. GILCHRIST, M.A., D.Sc. , Ph.D. , Professor of Zoology in the University of Cape Town , AND C. von BONDE , M.A., Lecturer in Zoology in the University of Cape Town . 1919. CAPE TIMES LIMITED, CAPE TOWN....

Owing to the fact that some of the types of animals available for the study of Zoology in South Africa differ from those described in text books for students in other countries, it has been found necessary to draw up special directions and diagrams for laboratory use in this country. These are now put in the more convenient form of a text book, which, though intended primarily for the use of the students of the University of Cape Town, may, it is hoped, prove useful to others engaged in the teac

External Characters. 1. Make a drawing of the animal viewed from above, showing:— ( a ) The nostrils. ( b ) The eyes. ( c ) The nictitating membrane and a short tentacle beneath the eye. [ The tentacle is absent in the Frog. ] ( d ) The tympanic membrane, which is not shown in the Platana, but is well marked in the Frog. ( e ) The opening of the cloaca. ( f ) The limbs and their divisions. ( g ) The skin with tube-like lines round the body. [ In the Frog these lines are not present. ] Fig. 1. —X

Skeletal System ( Part ). 1. Remove the pectoralis muscles covering the body between the arms to show the bones of the central part of the shoulder girdle and sternum, viz.:— ( a ) The thick coracoids. ( b ) The more slender clavicles anterior to them, both extending from the base of the arm on each side towards the centre of the body. ( c ) The sternum, consisting of a median row of cartilages which are believed to be derived from the shoulder girdle. It does not, therefore, correspond to, or i

Vascular System ( continued ). A. Venous System. 1. Note:— ( a ) The heart lying in the thin pericardium, the two auricles, the single ventricle, the truncus arteriosus which divides into two branches. Remove the pericardium from the heart, and tilt the apex of the heart forwards, noting the sinus venosus into which the right and the left superior venæ cavæ (or precavals) and the single inferior vena cava (or postcaval) open. ( b ) The veins passing from each side of the sinus venosus. Each supe

Arterial System ( continued ). 1. Trace the carotid arch, which gives off: ( a ) Two lingual arteries having a common point of origin near the carotid gland. ( b ) A carotid artery passing to the head. At its origin it is slightly swollen into the carotid gland. 2. Trace the systemic arches which run backwards on each side of the body, meeting posteriorly to form the dorsal aorta. Each systemic arch gives rise to an artery which branches into:— (i) A scapular artery to the pectoral girdle. (ii)

Skeletal System ( continued ). A. The Pectoral and Pelvic Girdles and Limbs. 1. Detach a fore-limb with the remaining parts of the pectoral girdle. Make a preparation showing these various parts:— Supra-scapula, scapula, remainders of the clavicle and the coracoid, humerus, radio-ulna, carpal bones, and digits. Draw these parts. Fig. 11. —Pectoral Girdle of Xenopus and Rana. 2. Detach the pelvic girdle from the transverse processes of the 9th vertebra. Remove it with the hind-limbs from the body

Skeletal System ( continued ). C. The Skull. 1. Remove the skin and other tissues from the top of the skull and observe the large fronto-parietals, nasals, supra-ethmoid, premaxillæ, maxillæ, squamosals, exoccipitals, and pro-otics. The quadrato-jugals are very inconspicuous. The extrastapedial plate of cartilage is well marked and the bony columella may be seen lying underneath it. The sides of the skull are ossified and may represent the orbitosphenoids and alisphenoids of higher types. The su

With a second specimen revise the second, third, and fourth days' work, paying particular attention to the vascular system....

Nervous System ( continued ). B. The Peripheral Nervous System. 1. The Spinal Nerves. Remove the abdominal viscera carefully so as to expose the spinal nerves which are seen as white cords on each side of the vertebral column as follows:— ( a ) The first or hypoglossal nerve arising between the 1st and 2nd vertebræ. It runs forwards on the under surface of the head beneath the mylo-hyoid muscle and supplies the tongue. It was noted in the third day's work. ( b ) The second and third nerves unite