40 CALIFORNIA ACADEMY OF SCIENCES. 



arched, the snout decurved, interorbital region flat. 

 Occipital process strongly keeled, reaching the narrow, 

 saddle-shaped dorsal plate; a groove from near the base 

 of the occipital process forward to the fontanel. Fon- 

 tanel consisting of three parts, the posterior a very 

 small triangular opening, the middle one an elliptical 

 opening Ih diameters of the eye in length, the anterior 

 one - half a diameter. Skin of the postorbital j^ortion 

 of the head very thin, the surface of the bones very 

 itrongly granulose, striate in the young. Snout and 

 sides of the head with vermiculating mucous canals. 



Eye elliptical, its longitudinal axis inclined, the 

 diameter 1-lh in the snout, 4-5 in head, ll-li in the 

 interorbital. 



Lips thick, upper jaw projecting; depth of the inter- 

 maxillary band of teeth 6 in its width ; a small subtrian- 

 gular patch of teeth, similar to one of 

 the small palatine patches, is contigu- 

 ous to the intermaxillary band, and 

 appears to form a backward projecting 

 angle to it; palatine teeth in numerous 

 small patches which are aggregated 

 into a large patch on either side, and attached to a 

 fleshy cushion, forming the sides of the strongly arched 

 palate; mandibulary teeth larger than the intermaxillary 

 teeth, in five or six irregular series, the depth of the 

 band about equal to the intermaxillary band, broadly 

 interrupted ill front; the teeth disappearing with age. 



Maxillary barbels reaching to the edge of the opercle, 

 a little longer in the young; mental and postmental 

 barbels inserted in a line parallel with the edge of the 

 mandible, reaching scarcely beyond the branchiostegal 

 membrane, or shorter. 



Gill-membranes united and joined to the isthmus, 

 leaving a narrow free margin. Gill-rakers 5-|-9. 



