SYSTEMATIC CATALOGUE OF FISHES. 341 



i. Dorsal spine comparatively stout, its posterior surface with retrorse barbs; pelvic bone sur- 

 mounted with a spine projecting through skin of abdomen; gill-openings short, and more 



or less vertical; caudal fin broad Monacanthus. 



ii. Dorsal spine rather slender, without barbs; no spine on pehdc bone; gill-openings long and 

 very oblique; caudal fin elongate Ceratacanthus. 



Genus MONACANTHUS Cuvier. File-fishes. 



A very numerous genus of small fishes with short, deep, much compressed 

 body; very small mouth; about 6 teeth in outer row and 4 in inner row in upper 

 jaw, and about 6 in lower jaw; gill-slit shorter than eye, slightly oblique, and 

 under posterior part of eye; minute scales, individually rough, but giving to the 

 skin a velvety feel; ventral flap and sometimes caudal peduncle spinous; large 

 dorsal spine, with 2 series of retrorse spines; second dorsal and anal fins with 

 25 or more rays; broad, rounded caudal; blunt, movable ventral spine; pelvic 

 bone united with abdomen by a broad flap of skin. Several American species, 

 1 common along our Atlantic coast. (Monacanthus, one spine.) 



294. MONACANTHUS HISPIDUS (Linnaeus). 

 "Fool-fish"; File-fish. 



Balistes hispidus Linnseus, Systema Naturse, ed. xii, 405, 1766; Carolina. 

 Stephanolepis setifer. Yarrow, 1877, 204; Beaufort. Jordan & Gilbert, 1879, 367; Beaufort. 

 Monacanthus hispidus, Jordan, 1886, 30; Beaufort. Jenkins, 1887, 93; Beaufort. Jordan & Evermann, 1898, 

 1715, pi. cclix, fig. 635. Linton, 1905, 401; Beaufort. 



File-fish. Monacanthus hispidiis. 



Diagnosis. — Depth contained 1.75 times in length in adults; head about 5 depth; pro- 

 file from dorsal spine to end of snout nearly straight; snout very long, about 3 times diameter 

 of eye; gill-slits length of eye; margin of abdominal flap not extending beyond ventral spine; 

 body completely scaly, each scale with 3 prickles; dorsal spine straight, above posterior part 

 of eye, shorter than snout, posterior surface with 2 rows of barbs; dorsal soft rays about 32, the 

 first ray often filamentous, the others becoming gradually sliorter from before backward; anal 



