In the course of examining material from fissure deposits of early Permian age collected from a limestone quarry near Fort Sill, Oklahoma, the author recovered several tooth-bearing fragments of small pelycosaurs. The fragments were examined, compared with descriptions of known kinds appearing in the literature, and determined to be new genera within the Nitosauridae (Edaphosauria) and Sphenacodontidae (Sphenacodontia). Appreciation is expressed to Prof. Theodore H. Eaton, Jr., for permission to

( delos , Gr., evident; rhynchos , Gr., neuter, nostril; priscus , L., ancient. Delorhynchus is masculine because of the ending that it acquires when transliterated into Latin.) Type specimen. —Fragmentary left maxilla, bearing four teeth, KU 11117. Referred specimens. —Fragmentary right maxilla having four teeth, KU 11118; fragmentary left maxilla having four teeth, the most posterior of which has been broken, KU 11119. Horizon and locality. —A fissure deposit in the Arbuckle limestone at the D

( Thrausmosaurus is formed from the neuter Greek noun, thrausma , meaning fragment, and the masculine Greek noun, sauros , meaning reptile. The specific name, serratidens , is formed from the Latin serratus , meaning serrate, and the masculine Latin noun, dens , meaning tooth. The specific name is used as a substantive in apposition with the generic name.) Type specimen. —Fragmentary left dentary, bearing five teeth, the most posterior of which is broken at the base, KU 11120. Referred specimens

Peabody, F. E.     1961. Annual growth zones in living and fossil vertebrates. Jour. Morph. 108 (1): 11-62, 69 figs., January. Romer, A. S.     1956. Osteology of the reptiles. The University of Chicago Press, Chicago, xxi + 772 pp., 248 figs. Romer, A. S. , and Price, L. I.     1940. Review of the Pelycosauria. Geol. Soc. America, Spec. Pap., 28: x + 538 pp., 71 figs., 46 pls., 8 tables, December 6. Vaughn, P. P.     1958. On a new pelycosaur from the lower Permian of Oklahoma, and the origin o