174 FISHES OF MASSACHUSETTS. 



Family IL 

 SCLERODERMI. 



MONOCANTHUS. CuV. 



Generic characters. Very, small scales, covered with stiff 

 and thickly set aspei'ities, like the pile on velvet ; extremity of 

 the pelvis salient and spinous as iti the true Batistes ; a sin- 

 gle large serrated spine in the first dorsal, or at least the second 

 one is almost imperceptible. 



M. Massachusettensis. Nobis. The Massachusetts File Fish. 



The only specimen I have seen was sent me by Dr. Yale, as 

 having been found in Massachusetts Bay. 



Its entire length is four inches ; depth across, from the base 

 of the dorsal spine, two inches ; depth at the base of the tail, 

 three lines. Body oblong, very much compressed ; surface 

 granulated, and exhibiting numerous minute white cilia sus- 

 pended from its sides. Color, a yellowish brown, variegated 

 over its entire extent with brownish markings and blotches, 

 which are less obvious beneath. Length of the head, one inch ; 

 jaws of equal length ; teeth stout. Eyes circular, one fourth 

 of an inch in diameter ; above, and just back of the eye, a 

 strong, granulated, curved spine, half an inch long, is situated, 

 with small sharp spines upon its posterior lateral edges, point- 

 ing downwards and backwards. 



The Dorsal fin commences three quarters of an inch back of 

 the spine ; composed of colorless rays, roughened at their 

 bases. The pectorals also, are colorless, and rounded when 

 expanded. 



The Pelvic bone projects, is quite moveable, and is connected 

 by a dewlap to the abdomen. 



The Anal fin is situated just back of the dorsal ; the base of 

 its rays are granulated like those of the dorsal ,• and it is of the 

 same form as that fin. 



The Caudal fin is darker colored than the other fins. 



The fin rays are : D. 34 ; P. 12 ; A. 34 ; C. 



