NATURAL SCIENCES OF PHILADELPHIA. 285 



tlian inferior. Scuta 1. 1. 28, 1. tr. 4. Inferior regions granular ; 

 dermo-ossification of head extending to inferior plane all around, 

 Orbit small, three times in interorbital width, five times in head, 

 width a little greater than length. A marked canthus rostralis 

 to beyond nares ; loreal region steep, concave. An occipital keel, 

 nuchal shields two-keeled. Elevation at latter, equal length 

 muzzle and orbit. 



Scales rugose, with a serrate median keel ending in a point. 



Above, brown ; below, yellowish-brown, closelj^ spotted with 

 dark brown, most coarsely on the bell}'', and finely on the head, 

 leaving vermicular interspaces ; eight rows of black spots on the 

 dorsal fin. Other fins, except the caudal, closely black-spotted. 



Length .18 m. ; to anal fin .085 ; to mandible .01. 



Numerous young specimens of this species, the largest .085 m. 

 in length, display the following characters of immaturity. The 

 inferior surfaces are smooth, and in the smaller the dermo-ossifi- 

 cation of the loreal region exists only in spots, and in still smaller 

 is wanting. 



Two large specimens from Perkin's expedition have the hume" 

 ral width and the total length, the base of the dorsal fin enters 

 the same 3.Y5 times, and is equal the length of the pectoral spine, 

 and the greatest depth of the body enters six times. The speci- 

 mens agree with Castelnau's L. pardalis in having dorsal radii 

 1.12, but ditTer in having no keel on each side of the back poste- 

 rior to the dorsal fin, and in having large spots on the belly, not 

 " pnnctse." The former character I derive from Castelnau's figure 

 only. 



The young of a second species of this genus occurs in the col- 

 lection. 



PLECOSTOMUS BISEEIATUS, Cope, sp. nov. 



Radii D. I. 7 ; A. 5 ; Y. I, 5 ; P. I. 6. Lateral series of scuta 

 28, three rows between ventral and dorsal fins. Elevation of first 

 dorsal ray equal length of head ; length of basis equal to dis- 

 tance from spine of adipose, and 1.66 times length of head and 

 nape. Scuta between dorsals 8, between anal and caudal 16. 

 Pectoral spine to basis of ventral. Scuta not carinate, coarsely 

 striate, the strise terminating in a few small spines. 



Head short, entering length without caudal fin 4.5 times, and 

 a little less than width. A postorbital and orbito-nareal angle, 

 rim of orbit elevated above front. An obtuse median occipital 

 1J572.J 



