336 
BULLETIN OF THE BUREAU OF FISHERIES 
examined by us had this body in position as explained; a third alcoholic specimen had the little 
solid body pushed into the cavity of the bladder and this gave the bladder the appearance of having 
a foramen. 
188. Rissola marginata (DeKay). Cusk eel. 
Ophidium marginatum DeKay, New York Fauna, Fishes, 1842, 315; New York Harbor. Bean, 1891, p. 85. 
Rissola marginata Jordan and Evermann, 1896-1900, p. 2489, PI. CCCLIII, fig. 868. 
Head 5.95 to 6.15; depth 7.3 to 8.2. Body quite elongate, compressed, of about uniform 
depth from nape to middle of anal base, then tapering to tail; head compressed; snout moderately 
pointed, 3.5 to 4.05 in head; eye 3.05 to 3.3; interorbital (bone) 4.75 to 6.85; mouth moderately 
large, horizontal; lower jaw included; maxillary reaching nearly or quite to posterior margin of 
eye, 2 to 2.15 in head; teeth in jaws pointed, in bands; vomer and palatines with bands of blunt 
teeth; gill rakers short, four to five on lower limb of first arch; lateral line usually not quite com- 
plete; scales small, elongate, imbedded, wanting on head; dorsal and anal fins long, low, con- 
tinuous with the round caudal; origin of dorsal over or a little behind middle of length of pectorals; 
origin of anal a little behind the beginning of the second one-third of body; ventral fins inserted 
below vertical from middle of eye, consisting of two filaments, the longest one about an eye’s 
diameter shorter than head; pectoral fins moderately large, 1.2 to 1.3 in head. 
Color in life grayish green; sides golden; belly snow white; ventral surface of head mostly 
golden; sides of head punctulated with brown; lateral line in a dark band; dorsal fin pale green 
with black margin, this color continued on caudal and posterior half of anal fin; margin on anterior 
half of anal white; ventrals white; pectorals golden with distal and lower margins white. The 
color in alcohol fades to a light brown; the fins pale, with margins as in the live fish. 
Fig. 202. — Rissola marginata. Adult, 8J4 inches long 
The cusk eei is represented in tlie present collection by five specimens, ranging in length from 
145 to 230 millimeters (5?4 to 9 inches) in length. This fish is readily distinguished from all others 
of Chesapeake Bay by its long, somewhat eel-like body and by the white, filamentous ventral fins 
(each fin with two slender filaments) situated behind the chin and below the eyes. 
Little is known about the life history of this fish. It appears to be nocturnal in its habits. An 
individual kept in the aquarium by one of us (Hildebrand), in the laboratory at Beaufort, N. C., 
remained concealed during the day in the sand placed in the aquarium. Frequently only a cur- 
rent of water could be seen where its snout was near the surface. At night, however, it frequently 
was seen swimming about in the aquarium, presumably searching for food. Its tail is supported 
by heavy cartilage radiating from the last vertebra and is used in burrowing in the sand, for it 
always descends into the sand with the tail down. 
Three examples were examined for food. All had fed on small crustaceans and one had also 
eaten a small fish — a goby. The ovary is single, showing a median fold, however. It is not known 
when spawning takes place. Three specimens examined were females, one taken on May 21, 
another on July 16, and the third on September 12; the ovaries of all appeared to be in an early 
stage of development. 
It is difficult to know, of course, how common a species like the present one (which apparently 
remains burrowed in the sand throughout the day) really is, without doing considerable collecting 
at night. Two of the specimens at hand were taken along a sandy beach with a seine at 3 o’clock 
in the morning, another was found dead on the beach, and two more were taken by the Fish Hawk 
in a beam trawl at a depth of 10 fathoms. It is not known to the writers whether this haul by 
