154 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



lower level in the Permian, and it is doubtful that they are conspecific 

 or congeneric with R. guadalupae. 



Judging from the only extant illustrations of R. guadalupae Shu- 

 mard (1859, pi. 11, figs. 6a-c) reproduced by Girty (1909, pi. 16, figs. 

 10-10b), it differs from the Glass Mountains specimens in its less at- 

 tenuate pedicle and brachial beaks, less inflated brachial beak, less 

 distinct fold, sulcus that begins farther posterior, more distinct beak 

 ridges and finer, more crowded costae. These are specific characters ; 

 to determine the genus of specimens in this group it is necessary to 

 study internal structures, shape of the anterior external surfaces, and 

 the nature of the anterior commissure. None of these features is present 

 on Shumard's illustrations or described in his account of the species. 



Girty's (1909) description of his lost specimen from the Glass 

 Mountains mentions flat costae, a small cruralium, and a small, hori- 

 zontal hinge plate with an apical perforation. These are features en- 

 tirely unrelated and dissimilar to King's specimens or his description of 

 Uncinuloides. Aside from the fact that the specimens are missing, diffi- 

 culty arises from the general similarity of the shape of species belong- 

 ing to several genera. Cooper and Grant (1962) argued that Shumard's 

 species is unidentifiable, but certainly not conspecific with King's speci- 

 mens; the generic position of Girty's specimen is unknown. Unfor- 

 tunately, King's generic name is tied to Shumard's indeterminate spe- 

 cies, so they introduced Torynechus as a new genus, citing King's 

 (1931, p. 112, pi. 35, fig. 6-7) specimen as holotype for the type species 

 T. caelatus Cooper and Grant ( 1962) . 



Range. — Known species of Torynechus are confined to the Leonard 

 Series of the West Texas Permian. 



TORYNECHUS CAELATUS Cooper and Grant 



Plate 24, figs. 1-10 



Uncinuloides guadalupensis (Shumard) KING, R. E., 1931, Univ. Texas Bull. 

 3042, p. 112, pi. 35, figs. 6-7; COOPER, G. A., 1944, in Shimer and Shrock, 

 Index foss. No. America, p. 315, pi. 120, fig. 49-51. 



Torynechus caelatus COOPER, G. A., and GRANT, R. E., 1962, Journ. Paleon- 

 tology, vol. 36, No. 5, p. 1129. 



Shell about average size for genus; outline moderately to broadly 

 subtrigonal or subpentagonal, sides diverging between 65 and 115 de- 

 grees, averaging about 90 ; profile narrowly subtrigonal ; commissure 

 uniplicate, fold behind commissure low, standing above flanks only at 

 anterior extreme, point of beginning not ascertainable ; sulcus shallow, 

 beginning 8-12 mm. anterior to pedicle beak. Costae fine, blunt crested, 

 beginning at beaks, adding anteriorly by intercalation or more rarely 

 by bifurcation, numbering 9 to 14 on fold, one less in sulcus, 10 to 22 

 on each flank ; anterior margins of shell abruptly bent to form flattened, 



