300 
ACTINOPTEKYGII. 
Specially characteristic of the freshwaters of North America, but 
also living in Eastern Siberia. 
The following extinct species have been described on imperfect 
evidence, but are not represented in the Collection ;— 
Catostomus cristatus, E. D. Cope, Proc. Acad. Nat. Sci. Philad. 
1883, p. 160.—Lower Tertiary; S.W. Idaho. [Hinder 
part of Tl. 
Catostomus shoshonensis, E. D. Cope, loc. cit. p. 159.—Ibid. 
[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 Sderognathus, but with 
pharyngeal bones expanded behind. 
The following species are recognised, but are not represented in 
the Collection :— 
Amyzon hrevipinne, E. D. Cope, Proc. Acad. Nat. Sci. Philad. 
1893, p. 402.j^Lower Tertiary; Smilkameen Eiver, 
British Columbia. 
Amyzon commune, E. I). Cope, Bull. U.S. Geol. Surv. Territ. 
vol. i. no. 2 (1874), p. 50, and Yert. Tert. Eorm. West, 
Book I. (Bep. U.S. Geol. Surv. Territ. vol. iii. 1884), 
p. 749, pi. V. fig. 2l/—Lower Tertiary; South Park, 
Colorado. [Nearly complete fish; National Museum, 
Washington.] 
Amyzon fusiforme, E. D. Cope, Bull. U.S. Geol. Surv. Territ. 
[2] no. 1 (1875), p. 5, and op. cit. 1884, p. 751.—Ibid. 
[Ditto.] 
Amyzon mentale, E. D. Cope, Proc. Amer. Phil. Soc. vol. xii. 
(1872), p. 481, and op. cit. 1884, p. 749, pi. lix. fig. 2, 
pi. lx. fig. 2.—Lower Tertiary; Osino, Nevada. [Imperfect 
fish; National Museum, Washington.] 
Amyzon pandatum., E. D. Cope, Bull. U.S. Geol. Surv. Territ. 
[2] no. 1 (1875), p. 4, and op. cit. 1884, p. 750.—Lower 
Tertiary; South Park, Colorado. [Ditto.] 
Genus CYPRINUS (Artedi), Linnaeus. 
[Syst. Nat. ed. 10, 1758, p. 320.] 
Snout rounded and obtuse ; ventral border of abdomen not com¬ 
pressed to a sharp edge. Pharyngeal teeth molariform, in three 
