104 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Genus 37. CYPSILURUS Swainson. 
Body elongate, broad above, somewhat compressed; head short, blunt, narrowed below; mouth 
small; jaws very short, about equal; chin without barbel; maxillaries not joined to premaxillaries; 
teeth very feeble or wanting; eyes large; gillrakers moderate; scales large, deciduous; no finlets; 
dorsal fin short, opposite anal; caudal widely forked, lower lobe the longer; pectoral fins very long, 
reaching past beginning of anal and serving as organs of flight, their great size enabling these fishes 
to sustain themselves in the air for some time; ventral fins large, posteriorly inserted, also used as 
organs of flight; air-bladder very large; no pyloric caeca. 
Species numerous, in all warm seas, living mostly in the open water and swimming in large schools; 
largely cosmopolitan, and any of the forms may be expected to be found within our limits. 
a. Second ray of pectoral divided (first simple); third and fourth rays longest. 
b. Ventral fins inserted about midway between pupil and last caudal vertebra. 
c. Dorsal and anal fins without black markings; ventrals pale. 
cl. Base of anal 1.66 in base of dorsal; pectoral 1.44 in length, reaching last ray of dorsal; ventrals 2.75 in body, reach- 
ing last ray of anal heterurus 
dd. Base of anal 2 in base of dorsal; pectoral 1.40 in length of body, the tip reaching end of dorsal fin; length of 
ventrals 2.89 in body, their tips nearly reaching last ray of anal lutkeni 
cc. Dorsal and anal fins marked with black; dorsal with one or more dark blotches; anal with a black spot on tips of 
third to sixth rays; ventrals black, with pale edgings and a white spot near base furcatus 
bb. Ventral fin inserted midway between posterior margin of preopercle and last caudal vertebra. 
e. Pectoral with posterior half rather abruptly black; anal white nigricans 
ee. Pectoral unicolor or nearly so, not abruptly black posteriorly. 
/. Dorsal fin slightly dusky, but without distinct markings; other fins faintly shaded, but without distinct black 
markings; pectoral reaching base of last anal ray; ventrals almost as far. D. 13; A. 10 lineaUis 
ff. Dorsal fin with a round, black blotch as large as eye on tips of middle rays; other fins all pale; pectoral reaching 
beyond tips of dorsal and anal. D. 12; A. 11 cyanopterus 
bbb. Ventral fins inserted at. a point midway between middle of opercle and last caudal vertebra (or between tip of 
snout and tip of upper lobe of caudal ) bahiensis, 54 
aa. Second ray of pectoral simple (like the first); third ray divided. 
j Snout more obtusely descending than in any other species, its length 4.5 in head gibbifrons 
54. Cypsilurus bahiensis (Ranzani). Volador. 
Head 4; depth 5; eye 3.1; snout 4.25; interobital 3; D. 13; A. 9; scales about 50. 
Body quadrate, stout, its width about two-thirds its depth; mouth small, snout short; eye large; 
top of head flat; pectoral very long, reaching last rays of dorsal and anal, second ray divided, third 
and fourth longest; ventrals long, longer than head, reaching nearly as far as tip of pectoral, their 
origin midway between last, caudal vertebra and middle of opercle; dorsal considerably in front of 
anal, its base nearly double that of anal; caudal widely forked, lower lobe the longer. 
'Color, bluish, silvery above, silvery on sides, white below; side of head silvery; pectoral nearly 
uniform dusky, paler at base, and bluish-silvery outside; ventrals and anal pale; dorsal pale; caudal 
somewhat dusky. 
Found in tropical seas, north to Cuba, and said to be one of the commonest species; reaches a 
length of 8 inches. One specimen flew aboard the ship off Mayaguez, January 20. 
Exoccetus bahiensis Ranzani, Nov. Comm. Ac. Sci. Inst. Bonon., V, 1842, 362, pi. 38, Bahia. 
Exoccetus vermiculatus Poey, Memorias, II, 300, 1861, Cuba. 
Exoccetus spilonopterus Bleeker, “Nederl. Tydschr. Dierk., Ill, 1863, 113,” Sumatra. 
? Exoccetus parrse Poey, Synopsis, 385, 1868, Cuba; description insufficient; taken from an old drawing. 
Exoccetus bahiensis, Jordan & Evermann, l.c., 739, 1896. 
Cypsilurus bahiensis, Jordan & Evermann, 1. c., 2836, 1898. 
Family XXV. AULOSTOMIDAi. The Trumpet-fishes. 
Body compressed, elongate, covered with small ctenoid scales. Lateral line continuous. Head 
long; mouth small, at end of a long, compressed tube. Lower jaw prominent, with a barbel at sym- 
physis. Premaxillaries feeble, not protractile; maxillary broad, triangular, with a supplemental bone. 
Teeth minute, in bands on lower jaw and vomer. Branchiostegals 4; gills 4, a slit behind fourth. 
Pseudobranchiae well developed. Gillrakers obsolete. Gill -membranes separate, free from isthmus. 
Air-bladder large. Spinous dorsal present, of 8 to 12 very slender free spines; the soft dorsal and 
