702 ZOOLOGY— FISHES. 



Scombrcsocklce. As compared with Apsopelix, Cope, from the Benton group 

 of Kansas, Syllcemus differs in the absence of dorsal radii or interneural 

 spines anterior to the line the ventral fins. There is doubtless some affinity 

 between the two genera, as the other characters are quite similar. I was 

 unable to detect a lateral line in Apsopelix. It is possible that a catalogue 

 name of Agassiz, viz, Calamopleurus (Poiss. Foss., v, 122), refers to this or 

 some allied genus, but I am unable to discover that it has ever been described. 



SYLLAKMUS LATIFRONS, Cope. 



Represented by the entire head and body of a fish as far as the basis 

 of the ventral fins, excepting the end of the muzzle. The scales are com- 

 pletely preserved, while only the bases of the fins remain. 



The body is subeylindric, while the head is broad and flat above. 

 The inferior side of the head is contracted, the coracoids forming a keel, 

 and the lower borders of the dentary bones being in contact. The angular 

 portion of the dentary is strongly grooved on its inferior surface, and the 

 proximal or anterior parts of the operculum display a radiate sculpture. 

 The top of the head is smooth, excepting a slight radiate sculpture of the 

 parietals. The outline of the parietals is subround and a little more 

 extended than that of the supraoccipital, which is a short longitudinal oval. 



There are twenty-six or twenty-seven longitudinal rows of scales, those 

 of the abdomen not differing from those of the sides. The lateral line runs 

 along the eighth below the dorsal fin, originating just above the base of the 

 pectoral fin. There are nine rows of scales between the occiput and the 

 first dorsal ray. I count the bases of fifteen dorsal radii, which are all fis- 

 sured anteriorly, excepting the first, which is rudimental. The anterior 

 rays are stouter than the posterior, and they embrace the posterior part of 

 the ray in front of them by the basal fissure. The posterior rays are much 

 narrowed and embrace but little. The pectoral rays are numerous. The 

 physiognomy of this fish is rendered peculiar by the depressed form of the 

 snout, with the narrow under jaw. It is impossible to be sure whether the 

 muzzle was elongate or not. 



