244 CALIFORNIA ACADEMY OF SCIENCES. 



the width. Head short, depressed and pointed; its 

 width little less than its length; its depth 1| in its length. 

 Bones of the head coarsely striate becoming granular 

 only on the outer margins of the buckler. Dorsal plate 

 with a backward process which has an inward project- 

 ing knob behind, the outer margin of which is serrate; 

 scapular processes on the sides extending down to the 

 humeral process. Superciliary margins slightly raised, 

 serrate in front of the eye; a deeply pectinate nasal 

 shield articulates with the somewhat granular or serrate 

 suborbital bones; fontanel elongate triangular, the pos- 

 terior wider end not even with the posterior margin of 

 the orbit. 



Eye well protected, li in the snout, 5 in the head, 

 1^—14 in the interorbital. 



Maxillary barbels reaching past the middle of the 

 pectoral spine; mental barbels not to the base, post- 

 mentals to the second third of the pectoral spine. 



Snout narrow, its width at the rictus 2-2| in the head, 

 its length less than its width. Upper jaw projects. Teeth 

 well developed, in moderate bands. 



Gill-membranes separate to below the middle between 

 the eye and preopercle; processes of the corocoids naked 

 below, their surfaces striate; otherwise the breast is cov- 

 ered with skin. 



First two lateral plates touching the process of the 

 dorsal plate above but not extending to the humeral pro- 

 cess below; the region in front of the first lateral plate 

 with two elongate dermal ossifications corresponding tO' 

 the hooks of the lateral plates. The highest plate, ex- 

 clusive of the first two, about two diameters of the eye 

 high; each with a compressed median hook and from, 

 none to two smaller spines below and from one to six 

 above the median hook. No plates on dorsal or ventral 

 surfaces. 



Humeral process very long and narrow, tapering back- 



