398 CALIFORNIA ACADEMY OF SCIENCES. 



i. Lat. 1. 28; eye 4-| in the snoiit, 8 iu the head, 3 in the iu- 



terorbital; outer caudal raj'^s little produced; middle caudal 



rays li-li in the head. Base of the dorsal fin equal to its 



distance from the caudal, or very little less. Ihnosus 347. 



ii. Lat. 1. 30. Eye 3* in the snout, 6-6^ in the head; base of 



the dorsal equal to its distance from the posterior margin 



of adipose fin. carinatus 348. 



ee. Tip of snout granular, occasionally naked in plecosio7mts. 



j. Lateral plates all more or less strongly keeled; nuchal plates 



conspicuoiisly bicariuate; shortest caiidal rays H in the head. 



Light brown, everywhere spotted with darker. Lat. 1. 26. 



j)lecostomus 349. 

 jj. Lateral plates scarcely if at all keeled. Lat. 1. 27-28. 



h. Head with vermiculating light and dark lines; ventral sur- 

 face with short ijurved bars; occipital plate margined by 

 three nuchal plates; superciliary edge raised. 



raillanti 350. 

 kk. Head with round spots; ventral surface plain; superciliarj' 

 edge scarcely raised; base of the dorsal less than its dis- 

 tance from the adipose fin. villarsii 351. 

 hh. Belly partially or entirely naked.* 



0. Belly covered with minute scutes, except a quadrate space between 

 the ventrals. biseriatus 353. 



00. Belly with scutes only on the sides, and sometimes a narrow strip 

 between the ventrals. 



p. Lat. 1. 27. Upper lateral plates with a strong median keel; head 

 with a strong occii^ital keel and smaller temporal keels; nuchal 

 plates bicarinate; a band between the pectorals, sides of the belly 

 and a narrow band between the ventrals covered with scutes; dor- 

 sal surface, sides and fins spotted with brown; ventral surface 

 plain. se.minndus 354. 



pp. Lat. 1. 30; lateral plates not keeled. aimce 355. 



000. Belly entirely naked. pantherinus 356. 



aa. Head without distinct ridges or keels; snout broad, rounded. 

 q. Belly entirely covered with granular plates. 

 r. Tip of snout naked. 

 ,s. Dorsal crossed by six or seven black zig-zag stripes; base of the 

 dorsal less than its distance from the adiiiose; 17 scutes between 

 the anal and the caudal. Lat. 1. 30. Brownish black with black 

 dots, largest on belly; rays of the caudal, pectoral and ventral fins 

 crossed by a number of black streaks. cordovoe 357. 



ss. Dorsal spotted or uniform dusky; base of the dorsal longer than 

 its distance from the adipose fin. Lat. 1. 26-27; occipital bdrdered 

 by a single plate. 



*352 \irescens Cope, should probably be placed here. 



