Cope.] '*^^' LJune 7, 



II. Anterior rays shorter, measuring the anterior half or a little more 

 of the base of the dorsal; (muzzle conic or ijrojecting). 



D. XXIV. A. VII. Depth 2j in length; liead 4.3 in same ; back 

 much elevated, anterior dorsal rays measure to the loth ray. 



C. GRATI. 



D. XXVIII, V. X. A. VII. Depth 2.5 in length; head 4.35 in smae; 

 scales 8-5; short, stout; long dorsal rays measure to 22 ray. 



C. THOMPSONI. 



D. XXVI-VII, V. X. Depth 3 times in lengtli, head 3.5 times; muz- 

 zle elongate conic; eye median, large; anterior D. rays not thickened, 

 nearly as long as base of lin. c. bison. 



D. XXVII to XXX; A VIII; scales 6-5; oblong, long dorsals to 22 ray 

 in adults; depth 2.7 in length, eye small anterior. c. cypiuktjs. 



D. XXX A. VII; anterior dorsal rays thickened, osseous, short, reach- 

 ing IGth ray; head small, 4.5 to 5 times in length; eye small anterior; 

 fusiform, depth 3 times in length. c. kummifer. 



In the number of the radii of the ventral and anal fins, the species arc 

 not always entirely constant ; thus in one, C. bison there are VI, in 

 another VII anals. In C. cyprinns some have IX and others X ventrals. 

 In young examples of the species just named, the long anterior dorsal 

 rays are longer than in the adult, but not so much so as to be confounded 

 Avith the long rayed species of section one. The margins of the scales in 

 this genus and Bubalichthys are serrate, their structure thicker than in 

 the Ptychostomi. 



Gill has adopted the genera of the Catostomi as left by Agassiz, while 

 Giinther rejects most of them. Moxostoma, Ptychostomus and Catosto- 

 mus I regard as distinct genera of the typical form, to which I add Pla- 

 copharynx. Of those with finer and more numerotis pharyngeal teeth, 

 Cyclei)tus is distinct in its completely ossified cranium, as I have pointed 

 out in an essay on the Cyprinidas of Pennsylvania. Bubalichthys is well 

 characterized by the form of its pharyngeal bones, as shown by Agassiz. 

 The remaining Rafinesquian genera, Carpiodes and Ichthiobus are but 

 doubtfully distinct from one another. Carpiodes is the older name, with 

 which Sderognathus, Cuv., Val., may be associated as a synonyme. 



Carpiodes cUfformis, Cope. 

 , Spec. nov. 



This species has a remarkably obtuse muzzle, Avhich with the large eye, 

 almost gives it the appearance presented by monstrous perch and carp 

 where the premaxillary bones are atrophied. Viewing the top of the 

 head from a position opposite a point mid-way between the dorsal fin and 

 end of the muzzle, the spine of the iwemaxillary bone is not visible. In 

 the C. selene these spines ai-e very distinctly prominent, in the C. cutisan- 

 serinus slightly so. 



The dorsal outline of this fish is arched, elevated to the anterior dorsal 

 radii, and then regularly descending. The long dorsal rays extended, 

 reach to beyond tlie origin of the caudal. Lateral line nearly straight, 



