356 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 
1882. Itslength to the end of the upper caudal lobe is 172 millimeters; 
to the origin of the middle caudal rays it measures 154 millimeters, 
which length is taken as the unit for comparison with parts of the body. 
DriaGnosis: Prionistius macellus ditters greatly from Triglops pingelii, 
particularly (1) in its more slender body, (2) in its shorter jaws, (3) in 
its longer dorsal and anal fins, (4) in its emarginate caudal, (5) in hav- 
ing the uppermost exserted pectoral ray considerably longer than the 
rays above it, (6) in the more advanced position of the ventral fin, 
which is also much shorter than in 7. pingelii, (7) in the greater num- 
ber of rays in its dorsal] and anal fins. 
These differences are clearly brought out in the table of measure- 
ments accompanying this description. By a very happy coincidence 
Captain Nichols, during the same cruise, obtained an individual of 
Triglops pingelii which is only 8 millimeters longer than the type of P. 
macellus, thus securing the first recorded Alaskan specimen of 7. pin- 
gelii, and at the same time adding an interesting new genus related to 
Triglops. 
DESCRIPTION: The body is slender and elongate; its greatest height 
equals the length of the lower jaw, and is contained 8 times in the unit 
of length. The height at the ventrals equals 4 of the distance of the 
pectoral from the tip of the snout, and is contained 84 times in the 
standard body length. The caudal peduncle is shorter than in 7. pin- 
gelii; its least height equals the width of the interorbital space. The 
length of the caudal peduncle, measured from the end of the anal fin 
to the origin of the middle caudal rays, is contained 7 times in the 
standard total length. There are no bony plates along the dorsal fins. 
The lateral line contains well developed ossoeus tubercles, and beneath 
it are ciliated scales similar to those of 7. pingelii ; the breast, however, 
unlike that of the species just named, is naked. 
The head agrees in the main with that of 7. pingelit, but is not so 
deep nor so wide; the jaws are about equal in front. The greatest 
length of the head is contained 4} times in the unit of length; its great- 
est width is slightly more than $ its length, and is contained 74 times 
in the standard body length. The width of the interorbital area, meas- 
ured on the bone, is nearly + of the long diameter of the orbit, which 
equals the snout in length. On the top of the head, close behind the 
orbits, are two short, interrupted furrows similar to those observed in 
some species of Prionotus. The length of the upper jaw is contained 
24 times in that of the head, equals that of the postorbital part of the 
head, and is contained 94 times in the unit of length. The maxillary 
extends nearly to the vertical through the middle of the eye, the man- 
dible nearly to that through the posterior margin of the eye. The 
length of the mandible is about 4 that of the head. The dentition is 
the same as in J. pingelii. The length of the eye equals that of the 
snout, and is contained 34 times in the length of the head. The branch- 
iostegal membrane is not very deeply emarginate, and is free from the 
