SILUBlmH. 
329 
Genus RHINEASTES, Cope. 
[Proc. Amer. Phil. Hoc. vol. xii. 1872, p. 480.] 
An imperfectly known genus related cither to Pimelodus or to 
diius. Head depressed and bones of cranial roof marked with 
conspicuous rugosity ; frontal fontanelle closed, but marked by a 
smooth deep groove. Teeth minute and villiform, extending over 
vomer. Pectoral fin with robust spine, serrated on one or both 
borders ; a nuchal shield between the supraoccipital and the spine 
°f the dorsal fin. 
In the typical species, P. peltatus, the nuchal shield is large and 
massive ; in the other Eocene species (forming sub-genus Astephus, 
f^ope) it is narrow and short. 
The genus is known only by fragments from the Lower Tertiary 
°f North America, and is not represented in the Collection. The 
following species have been named : — 
Rh Wastes arcuatus, E. I). Cope, Ann. Kep. U.S. Geol. Surv. 
Territ. 1872 (1873), p. 641, and Vert. Tert. Eorm. West, 
Hook I. (Itep. U.S. Geol. Surv. Territ. vol. iii. 1884), p. 6(1, 
pi. v. fig. 12. Pimelodus antiquus, J. Leidy, Proc. Acad. 
Nat. Sci. Philad. 1.873, p. 99 (name only), and Contrib. 
Extinct Vert. Fauna W. Territ. (Pep. U.S. Geol. Surv. 
Territ. vol. i. 1873), p. 193, pi. xxxii. figs. 44, 45.— Bridger 
Eocene; Upper Green Hirer, Wyoming. [Pectoral fin- 
spine ; National Museum, Washington.] 
Phineastes calvus, E. D. Cope, loc. cit. 1872 (1873), p. 640, and 
»p. cit. 1884, p. 65, pi. v. figs. 3 - 4 .— Bridger Eocene; 
Upper Green ltivcr. [Portion of cranium ; National 
Museum, Washington.] 
Phineastes qiectinatus, E. 1). Cope, Bull. U.S. Geol. Surv. Territ. 
vol. i. no. 2 (1874), p. 49, and op. cit. 1884, p. 74 1 , 
pl. v. fig. 13. — Lower Tertiary: South Park, Colorado. 
[Eragmout of head and anterior abdominal region ; National 
Museum, Washington.] 
Phineastes peltatus, E. D. Cope, Proc. Amer. Phil. Soc. vol. xii. 
(1872), p. 486, and op. cit. 18S4, p. 63, pl. v. figs. 1, 2.- 
Bridger Eocene ; South Bitter Creek, Washakie^ Basin, 
Wyoming. [Associated head -bones, &c. ; National 
Museum, Washington. The type species.] 
Phineastes (?) rhmas, E. D. Cope, Contrib. Canadian Palaeont. 
(Geol. Surv. Canada), vol. iii. (1891), p. 3, pl. i. fig. 3. 
Lower Miocene; Cypress Hills, N.W. Territory, Canada. 
[Vertebras; Canadian Geol. Surv. Museum, Ottawa.] 
