248 CALIFORNIA ACADEMY OF SCIENCES. 



depth, 1| in its length. Top of the head granular-stri- 

 ate, the obtuse keel of the posterior part of the head 

 simply striate. Opercle with radiating ridges, granular 

 on its upper portion. Dorsal plate continued beyond 

 the dorsal spine, with a broad descending process behind. 

 Interorbital region nearly flat; profile almost straight 

 and moderately steep. Fontanel narrow, not extending 

 beyond the middle of the eye, but continued backward 

 as a groove. 



Eye considerably behind the middle of the head; 4i-5| 

 in the snout, 8J-9J in the head, 3-3^ in interorbital. 



Barbels thick at base, thickly papillose; maxillary bar- 

 bels extending to the posterior margin of the eye; men- 

 tals half as long as the postmentals which are a little 

 shorter than the maxillaries. 



Snout long and pointed, covered with smooth skin, 

 its width at the rictus 3i-3 in the head. Lips thick, the 

 lower one thickly papillose. Distance of the anterior 

 nares from the tip of the snout much greater than from 

 the posterior nares. Teeth none. 



Gill-opening extending to below the posterior angle 

 of the preopercle. Breast entirely covered with skin. 



Lateral scutes low, those between the ventrals and 

 anal highest. Each scute with a strong median hook; 

 the posterior half of the surface above and below cov- 

 ered with numerous short spines. Three small imbed- 

 ded plates in the humeral region. No plates on dorsal 

 or ventral surface. Snout with numerous small pores; 

 a few conspicuous canals on humeral region and below 

 and between the eyes. Sides and back covered with mi- 

 nute circular or oval warts (in the adult). 



Humeral process extending to the posterior third of 

 the pectoral spine; its surface sharply granular; a median 

 ridge with a single series of spines in the young. Pec- 

 toral pore simple. 



