354 
BULLETIN OP THE BUEEAU OF FISHERIES 
No specimens of this species are at hand, nor was it observed by collectors or reported by 
fishermen during the present investigation. This account is included because of a record by Uhler 
and Lugger (1876), who mention a mouse fish, under the name Pterophryne Isevigata, as occurring 
in the “oyster regions of Chesapeake Bay.” It is difficult to understand what connection this 
pelagic fish could have with oyster regions. It probably was taken in such areas quite by accident. 
The mouse fish is recognized by its naked body, small oblique mouth, projecting lower jaw, hand- 
like pectoral fins, and its yellowish color, which is marbled or blotched with brown. 
The habits of the sargassum fish are not well known. It is usually found among floating 
seaweed, to which it attaches itself by means of its handlike pectorals. In this way it is drifted 
far and wide by winds and currents. In the aquarium it is cannibalistic, attacking its fellows, 
biting off their fleshy appendages and swallowing its smaller companions. It is probably safe to 
conclude from such a display of voracity that it is naturally carnivorous in its habits. 
The following account relative to the spawning of this fish is quoted from Smith (1907, p. 400). 
Nothing, so far as we are aware, has been added to our knowledge of this fish since this was written. 
Our knowledge of the spawning habits and eggs of the species depends almost entirely on observations at the Government 
laboratories at Woods Hole and Beaufort. The spawning season is from July to October, and a number of captive specimens have 
laid their curious egg rafts while in aquaria. The eggs are deposited in a bandlike or ribbonlike mass, from 1.5 to more than 3 feet 
long, about 3 inches wide, and 0.25 inch thick; they are only one-fortieth inch in diameter and very numerous, and are held together 
by a transparent jelly, which is buoyant. Nothing is known about the embryology, as eggs have not been fertilized. On July 
25, 1903, a fish 3.5 inches long, which had been at the Beaufort laboratory for seven weeks, laid a mass of eggs three times as large 
as the fish. 
The maximum size attained by this fish is reported to be 6 inches. It is not taken in large 
numbers anywhere along the coast, and because of its peculiar shape, handlike pectoral fins, and 
bright color it is usually regarded as a curiosity. It has no commercial value. In Chesapeake 
Bay it evidently is extremely rare, and it does not occur there except as it may rarely be drifted 
into this water by favorable winds and currents. 
Habitat . — Tropical Atlantic; occasionally drifted northward, probably in the Gulf Stream, 
on the coast of America as far as Woods Hole, Mass. 
Chesapeake localities. — (a) Previous record: “Occurs in the oyster regions of Chesapeake 
Bay, but is perhaps quite uncommon” (Uhler and Lugger, 1876). (6) Specimens in collection: 
None. 
Family XCIV.-OGCOCEPHALID/E The batfishes 
Body depressed, the trunk short and slender; head very broad, much depressed; snout more 
or less elevated, usually projecting; mouth not large, usually inferior, the lower jaw included; 
teeth pointed; gill openings small, above and behind axils of pectoral fins; skin covered with bony 
tubercles or spines; a rostral tentacle, retractile into a cavity under the rostral process, usually 
present; dorsal and anal small; ventrals present; pectorals well developed, with strongly angled 
base. Peculiarly shaped fishes, most of them apparently sluggish in their movements. Some 
of the species live along the shores in very shallow water and others inhabit the deep sea. 
160. Genus OGCOCEPHALUS Fischer. Batfishes 
Body depressed; head broad, triangular or more or less disklike in form, not broader than 
long; snout provided with rostral projection, varying greatly in length; eyes rather large, lateral; 
mouth moderate, inferior; teeth in villiform bands on jaws, vomer, and palatines; gill opening 
small near inner axil of pectoral; gills 2}^; skin rough, with bony tubercles; a dermal tentacle present 
under the rostral process, retractile into a well-developed cavity; ventrals I, 5, well separated; 
pectorals large, placed horizontally. 
