FISHES OF MASSACHUSETTS. 175 



ALUTERES. Cuv. 



Generic characters. An elongated body covered with small, 

 and scarcely visible granules ; a single spine is the first dor- 

 sal ; the chief character is in the pelvis, which is completely 

 hidden under the skin, and is without that spinous projection 

 observed in the other Balistes. 



A. monoceros ? Bloch. The Unicorn File Fish. 

 Shaw's Zoology, vol. v. pi. H. p. 399, et fig. 



To Dr. Yale I am indebted for the specimen before me ; 

 I have met with no other individual of this species. 



Length, three inches ; depth across, from the base of the 

 dorsal spine, half an inch ; depth at the base of the tail, one 

 line. Color, a light brown, mottled by a darker brown, which 

 is deepest above ; neck, silvery. Surface of the fish, almost 

 smooth to the touch ; but presenting a granulated appearance 

 under the glass. Length of the head, half an inch, gradually 

 arching from the tip of the snout to the spine ; lower jaw 

 slightly projecting ; teeth moderate in size. Eye circular ; di- 

 ameter of the eye, less than a line. Just over the posterior 

 margin of the orbit of the eye, a slender, roughened spine, one 

 fourth of an inch high. 



The Dorsal fin arises half an inch back of the spine ; com- 

 posed of delicate, transparent, colorless rays. 



The Pectorals arise on a line with the dorsal spine. 



The Anal fin formed like the dorsal, arises on a line with, 

 and terminates just back of that fin. 



The Caudal fin. is dark brown : the upper and lower rays the 

 shortest ; the middle are the longest ; and to the former, in 

 length, as 6 to 1. 



The fin rays are : D. 34; P. 10; A. 34; C. 12. 



