300 
ACTIN OPTERT SIX. 
Specially characteristic of the freshwaters of North America, but 
also living in Eastern Siberia. 
the following extinct species havo been doscribed on imperfect 
evidence, but are not represented in the Collection : — 
Catostomus crigtatus, E. D. Cope, Proc. Acad. Nat. Sci. Philad. 
1883, p. 160. — Lower Tertiary; S.W. Idaho. [Hinder 
part of skull.] 
Catostomus shoshonensis, E. D. Cope, loc. cit. p. 159. Ib' ( b 
[Skull.] 
Genus AMYZON, Cope. 
[Proc. Amer. Phil. Soc. vol.xii. 1872, p. 480.] 
An extinct genus related to Catostomus, but with more extended 
dorsal fin. Scarcely distinguishable from Scleroynathus, but " 11 1 
pharyngeal bones expanded behind. 
Tho following species are recognised, but are not represented 1,1 
the Collection : — 
Amyzon hrevipinne, E. D. Cope, Proc. Acad. Nat. Sci. Philad. 
1893, p. 402. — Lower Tertiary ; Smilkamcen Biver, 
British Columbia. 
Amyzon commune, E. I). Cope, Bull. U.S. Geol. Surv. Tcrnt. 
vol. i. no. 2 (1874), p. 50, and Vert. Tert. Norm. Wes , 
Book I. (ltep. U.S. Geol. Surv. Territ. vol. in- 188 ,'’ 
p. 749, pi. v. fig. 21. — Lower Tertiary; South Pa 1 "’ 
Colorado. [Nearly complete fish; National Museum 
Washington.] 
Amyzon fusiforme, E. D. Cope, Bull. U.S. Geol. Surv. Terri . 
[2] no. 1 (1875), p. 5, and op. cit. 1884, p. <51. 
[Ditto.] 
Amyzon mentale, E. D. Cope, Proc. Amer. Phil. Soc. vol. XI '' 
(1872), p. 481, and op. cit. 1884, p. 749, pi. lis. « 
pi. lx. fig. 2. — Lower Tertiary; Osino, Nevada. [Impe r 
fish ; National Museum, Washington.) 
Amyzon pandatum , E. D. Cope, Bull. U.S. Geol. Surv. Tern • 
[2] no. 1 (1875), p. 4, and op. cit. 1884, p. 750. 
Tertiary ; South Park, Colorado. [Ditto.] 
Genus CYPRINUS (Artedi), Linnmus. 
[Syst. Nat. od. 10, 1758, p. 320.] 
Snout rounded and obtuse ; ventral border of abdomen not con 
pressed to a sharp edge. Pharyngeal teeth molariform, in *- irt 
