FISHES OF CHESAPEAKE BAY 
309 
131. Genus CHAJTODON Linnaeus. The butterfly fishes 
Body short, deep, much compressed; head short; snout pointed; mouth small, terminal; teeth 
in the jaws in bands, numerous, slender, and flexible; scales firm, ctenoid; dorsal fin long, continu- 
ous, with about 12 or 13 spines; caudal fin straight or round; anal fin with three spines, the soft part 
similar to that of the dorsal; ventral fins thoracic, with a strong spine. A single species of this genus 
of tropical fishes comes within the scope of the present work. 
168. Chaetodon ocellatus Bloch. Butterfly fish. 
Chsetodon ocellatus Bloch, Ichthyol., 1787, p. 11, PI. 210, fig. 2; Jordan and Evermann, 1886-1900, p. 1674, PI . CCXLIX, fig. 621. 
Head 2.55; depth 1.55; D. XII, 21; A. Ill, 17; scales 36. Body very deep, strongly com- 
pressed; anterior profile nearly straight (notably concave in adult); head short and deep; snout 
pointed, 2.95 in head; eye 2.3; interorbital 2.9; mouth very small, terminal; teeth in the jaws 
flexible, in bands; gill membranes attached to the isthmus; lateral line running high and ending 
under posterior part of dorsal fin; scales ctenoid, rather large on sides, reduced on head and caudal 
peduncle, the rows running obliquely upward and backward on upper portion of side; dorsal and 
anal both scaled; the dorsal long, its origin over upper angle of gill opening, the spines strong; 
caudal fin nearly straight; anal fin with three strong spines, the soft part similar to that of the dorsal; 
ventral fins inserted under base of pectorals; pectoral fins rather broad, 1.3 in head. 
Color grayish to yellowish; a jet black bar, about two-thirds the width of eye, extending from 
the origin of the dorsal, through eye, to the lower margin of preopercle; a second indefinite bar 
running from middle of anal to middle of soft part of dorsal (this band is present only in the young) ; 
fins all more or less orange, middle of soft part of dorsal with a large black blotch. 
A single specimen, 35 millimeters in length, was secured. Its short, deep form, pointed snout, 
and the black band extending from the nape, through the eye, to the lower margin of the head 
serve well to distinguish the butterfly fish from all other fish of Chesapeake Bay. 
Nothing is known of the spawning and feeding habits of this showy little fish, which probably 
rarely exceeds a length of 6 inches. It has no commercial value. 
Habitat . — Woods Hole, Mass., to the Isthmus of Panama; probably more common in the 
West Indies than elsewhere within its range. 
Chesapeake localities. — (a) Previous records: None. (6) Specimen in collection: From end 
of Cape Charles, Va., caught September 20, 1921. Apparently very rare within the bay, as only 
this single specimen was seen. 
Order CATAPHRACTX 
Family LXXIV.-HEMITRIPTERID&. The sea ravens 
Body elongate, robust anteriorly; head large, bony; eyes large, placed high, in anterior half 
of head; interorbital space concave; mouth large; teeth in jaws in bands; preopercle with spinous 
processes; suborbital connected with preopercle by a bony stay; gill membranes united, free from 
the isthmus; gill arches 4, the slit behind the last obsolete; gill rakers rudimentary; body largely 
covered with prickles and dermal appendages; lateral line present; vent situated in anterior half 
of body; dorsal fins 2, separate, the first one with about 16 weak spines; anal fin with about 13 soft 
rays and no spines; caudal fin round; ventral fins thoracic, with one spine and three unbranched 
soft rays; pectoral fins moderate, with broad bases. Vertebrae 16 + 23; myodome much contracted 
behind. 
132. Genus HEMITRIPTERUS Cuvier. Sea ravens 
Body moderately elongate; head large, with numerous bony humps, ridges, and fleshy flaps; 
orbital rim much elevated; interorbital space deeply concave, followed by two blunt spines on each 
side; mouth large; teeth in broad bands on the jaws, vomer, and palatines; no slit behind the last 
gill; gill membranes broadly united, free from the isthmus; preopercle with stout, blunt spines; 
suborbital stay forming a sharp ridge; scales wanting; the skin covered with prickles and bony 
protuberances; spinous dorsal much longer than the soft part, with 16 to 18 spines; ventral fins 
with I, 3 rays; pectoral fins very broad. 
