470 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 
4.15 (4.2) times in the head, extends backward almost to below the 
hinder margin of the pupil. The outer series of premaxillary teeth 
are scarcely enlarged. The free portion of the small barbel is con- 
tained but 7.2 (6.2) times in the postorbital. Fhe gill-membranes 
cross the isthmus with a narrow free fold; six branchiostegals, 
The center of the anus is distant from the anal, the interspace being | 
half the distance from the anus to the base of the outer ventral ray, 
a distance which is contained 1.2 times in that between the ventral 
and the isthmus, or 1.3 (1.4) times in the postorbital. There is no 
trace of a ventral fossa in front of the anus nor between the ventrals. 
The scales are smaller and more closely imbricate than in the fol- 
lowing species, there being 64 in a series from the origin of the 
second dorsal fin to the lateral line series. The scales are less strongly 
Fig. 18.—CoRmLORHYNCHUS DORSALIS. TYPE. 
spinous than in argus and macrolepis, but their carinae are more dis- 
tinctly developed, numbering 8 to 11 on each scale (5 to 7 in the 
smaller paratype). Each of the carinae bears 12 or fewer short, 
sharp, close-set spinules directed backward, the last one projecting 
slightly beyond the margin of the scale. In general the squamation 
of the head is similar to that of notatus, sexwradiatus, and triocellatus, 
but a few differences are apparent: the carinae on most of the scales 
of the head are similar to those of the body; they are usually more 
divergent, weaker, and smoother than in the preceding species. The 
dorsoterminal plate is shorter than in ¢réocellatus but more prominent 
than in notatus and seawradiatus; its dorsal length is contained 3.3 
times in the postorbital (4.1 times in the paratype). Seven scales 
cover the ethmoid portion, and 10 or 11 (9) the preorbital portion 
of the infraorbital ridge. Over the mediorostral ridge there are but 
8 narrow scales, each more oval than in the preceding three species, 
and armed with spinous carinae radiating from near the center of 
