PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 271 
assume error on his part in reference thereto, and, consequently, we 
propose (provisionally at least) to differentiate the two forms as follows: 
EURYPHARYNX. 
Eurypharynx Vaillant. Comptes Rendus Acad. Se. Paris, t. —, p. 1232, Dec. 11, 1882 
(tr. Ann. & Mag. Nat. Hist. (5), v. 11, p. 67). 
Eurypharyngids with the cranium prolonged backwards, the denti- 
gerous bones little more than three times as long as the cranium ;* 
“faint dentary granulations” on both jaws, and at the extremity of the 
mandible “two hooked teeth”; + and the tail terminating in a point. 
EURYPHARYNX PELECANOIDES. 
Eurypharynx pelecanoides Vaillant. 
GASTROSTOMUS. 
Gastrostomus Gill & Ryder. 
Eurypharyngids with the cranium abbreviated and little or no longer 
than broad, the dentigerous bones almost seven times as long as the 
cranium; minute acute conic teeth depressed inwards in a very narrow 
band on the jaws (no enlarged teeth at the extremity of the mandible), 
and the tail with an eradiate membrane under its terminal portion. 
GASTROSTOMUS BAIRDII. 
Gastrostomus bairdii Gill & Ryder. 
The cranium forms about one-thirtieth or less of the extreme length, 
and is as broad as long; the jaws are excessively elongated, being nearly 
(in large) or more (in young) than seven times longer than the cranium; 
there are about 160 rays in the dorsal fin and about 107 in the anal; the 
pectorals are very small, being only about as long as the diameter of 
the eye, and little more than twice as long as wide at the base, and 
have about nine simple rays. The rays of the unpaired fins are quite 
flexible in the small individuals, but quite rigid and more perfectly 
ossified in the larger; they become obsolete toward the end of the tail. 
The rays, which are rigid and well ossified anteriorly, become shorter, 
* «This animal, about 0.47 metre long and 0.02 metre high at the most elevated 
part, is of an intense deep black color. The body, the form of which is masked in 
front by the abnormal mouth, which will be mentioned further on, resembles that of 
Macrurus; it becomes regularly attenuated from about the anterior fourth, the point 
at which the external branchial orifice is seen, and terminates in a point at the caudal 
extremity ; the anus issituated at the junction of the anterior third with the posterior 
two-thirds of the body. 
“What gives this fish a very peculiar physiognomy is the arrangement of the jaws 
and the structure of the mouth, which are even an exaggeration of what Mr. Ayres 
has described in Malacosteus niger. Although the head is short, scarcely 0.03 metre, 
the jaws and the suspensorium are excessively elongated ; the latter did not measure iess 
than 0.095 metre ; and from this it results that the articular angle is carried very far 
back, to a distance from the end of the muzzle equal to about three and a half times the 
length of the cephalic portion.” 
t‘*On both jaws one can feel faint dentary granulations; at the extremity of the 
mandible there are two hooked teeth 0.002 metre long.” 
