396 CALIFORNIA ACADEMY OF SCIENCES. 24 
Body comparatively elongate, the head depressed but 
not very broad, somewhat broader than high; eye rather 
large, 5 to 6 in length of head; width of interorbital 
space, 2% in head; breadth of mouth, 23; length of 
snout, 3. 
Teeth all villiform; bands of vomerine teeth separated 
by a rather wide interval, each small, roundish, confluent 
with the neighboring palatine band, the junction marked 
by a slight constriction; palatine bands ovate, broad be- 
hind, varying considerably in size and somewhat in form, 
the width ranging from one-third diameter of eye to two- 
thirds, being generally largest in adults; band of palatine 
teeth without backward prolongation; band of maxillary 
teeth rather broad and short, its length about five times 
its breadth. Maxillary barbel broad and flattened at 
base, reaching a little past base of pectoral in the young, 
scarcely to the gill opening in the adult; outer mental 
barbels, 2 in head, inner 3. Gill-rakers, 44-12. 
Dorsal shield very short, narrowly crescent-shaped, its 
length on the median line not more than half that of one 
of its sides. Occipital process subtriangular, not quite 
as long as broad at base, with a strong median keel, its 
edges slightly curved. A short distance in front of the 
beginning of the keel is the end of the very narrow groove- 
like fontanelle, which is somewhat widened anteriorly, 
finally merging into the broad, flat, smooth interorbital 
area, the boundaries of which are not well defined; shields 
of head usually smooth, all finely and very sparsely gran- 
ular, the granules not forming distinct lines. 
Gill membranes forming a rather broad fold across 
isthmus. 
Dorsal spine long, usually, but not always, shorter than 
the pectoral spine, about 134 in head; axillary pore ab- 
sent. Humeral process rather broadly triangular, not 
