174 FISHES OF MASSACHUSETTS. 



Family II. 

 SCLERODERMI. 



MONOCANTHUS. CuV. 



Generic characters. Very small scales, covered with stiff 

 and thickly set asperities, like the pile on velvet ; extremity of 

 the pelvis salient and spinous as in 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 fomrd 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. 



