COPE ON CEETACEOUS AND TERTIARY FISHES. 71 



cephalic serration, and with minute teeth. The fishes here referred to 

 this genus do not exhibit any teeth ; but as my specimens, five in 

 number, are small, it is not certain that adults may not display them. 

 The presence or absence of teeth is not a constant character in all 

 Clupece, according: to Giinther. Leptosomus v. d. Marck does not appear 

 to me to differ from Sardinius. 



The Sardinius nasutulus is a small species of moderately elongate 

 form, with a rather long head and protuberant muzzle. The dorsal fin 

 originates in front of the middle of the body, and the ventral fins take 

 their rise immediately below its anterior rays. The anal originates 

 behind the line of the dorsal, but far enough forward to leave an elon- 

 gate caudal peduncle, which is also quite stout. The pectoral fins reach 

 nearly to the base of the ventrals. Eadii : D. 9 ; A. 11, about ; V. about 

 8. The boundaries of the scales are difficult to define on the specimens, 

 but there do not appear to be more than eight or ten longitudinal 

 series. Their sculpture consists exclusively of concentric grooves. 

 There are fourteen dorsal and fifteen caudal vertebrae, all with long and 

 slender neural spines. Of the former, five are anterior to the first inter* 

 neural bone, which is directed downward ; the last caudal vertebra is 

 slender and turned upward. The scales are very much attenuated, 

 so that their number cannot be made out. The ribs are stout for the 

 size of the fish. The superior surface of the head is rather narrow, and 

 tapers with straight borders to the muzzle. 



Measurements. 



M. 



Length of head (including operculum) 0.0115 



Length to base of dorsal fin (axial) 0.0175 



Length to base of ventral fin (axial) 0.0170 



Length to base of anal fin (axial) .,.. 0.0280 



Length to base of caudal fin (axial) 0. 0410 



Length of base of dorsal fin 0.0055 



Length of base of analfia 0.005? 



Width of skull between orbits 0.0010 



Depth of body at first dorsal ray 0. 0065 



Depth of body at middle of caudal peduncle 0. 0050 



Niobrara Cretaceous No. 3 of Dakota (Dr. Hayden). 



Sardinius lineatus, sp. nov. 



Two specimens of similar small size constitute the basis of informa- 

 tion respecting this species. Many characters can be derived from 

 these; bub the dorsal fin being absent from one of them, and the ven- 

 trals and posterior part of the body from the other, the mutual relation 

 of these fins is not ascertained. The form is very elongate, and the 

 head is lanceolate. The dorsal fin is distant from both cranium and 

 caudal fin. The fins are composed of slender rays, and the anal is not 

 elongate ; the caudal is deeply forked, and no vertebrae are included 

 behind the basis of its external rays, although four are embraced within 

 the convergent lines of the anterior upper and lower fulcra. The ver- 



