176 FISHES OF MASSACHUSETTS. 



OsTKACioN. Lin. 



Generic characters. Head and body covered with regular 

 bony plates soldered in such a manner as to form a sort of in- 

 flexible shield, which invests them so that the only movable 

 parts are the tail, fins, mouth, and a sort of small lip with 

 lohich the edge of their gills is furnished, all passing through 

 holes in this coat of m,ail. Jaws armed with ten or twelve 

 conical teeth. A single dorsal and ventral fin. 



O. Yalei. Nobis. Yale's Trunk Fish. 

 Journal of the Boston Soc. of Nat. Hist. vol. i. p. 353, et fig. 



The only specimen which has been found of this species 

 upon our coast, was discovered aUve by Dr. Yale in 1833, 

 among the sea-weed on the beach at Martha's "Vineyard, and 

 presented by him to the Boston Society of Natural History. 

 In 1836, I read a description of this fish to the Society above 

 mentioned, associating with it the name of the gentleman by 

 whom it was discovered, as a deserved respect due him by the 

 Society, for his frequent donations to their cabinet, and his 

 zeal for natural science. My sense of personal obligation to 

 him may, in some slight measure be conceived of from the nu- 

 merous references made to his kind attentions throughout the 

 pages of this Report. 



The description from the " Society'' s Journal,''^ I extract as 

 follows : 



" Body triangular ; all the upper portion, of a light lurid ap- 

 pearance, covered with hexagonal plates, each containing six 

 raised lines ; two subcaudal spines, short and somewhat in- 

 curved ; back of the dorsal fin, a large isolated plate three 

 quarters of an inch in length, composed of portions of the sev- 

 eral plates, separated from the rest of the horny cuticle by a 

 continuation of the ligamentary substance in which is imbed- 

 ded the fin. Form of the body, very similar to the bicaudalis ; 

 the entire surface, as far back as the dorsal and ventral fins, is 

 covered with hexagonal divisions or plates ; these are very 

 large back of the eyes and ventral fins, and include an im- 



