FISHES OF MASSACHUSETTS. 27 



one third length of head : distance between eyes equal to five 

 eighths the diameter of the eye. Jaws armed with numerous, 

 minute, sharp teeth : upper jaw very protractile — an emargina- 

 tion in its centre, into which the extremity of the lower jaw 

 shuts, when the mouth is closed. Chin prominent. Teeth in 

 vomer and palatine bones. 



The lateral line arises above the operculum, and taking the 

 curve of the body, terminates at the caudal rays : about thirty- 

 six sharp points are seen in the course of the lateral line. 



The Dorsal fin commences on a line with the upper opercu- 

 lar spine, its anterior half composed of spinous rays ; the 

 length of its highest rays equal to about one third the length 

 of the fin : posterior half of fin composed of membranous rays , 

 length of this portion equal to one half the length of spinous 

 portion. 



The Pectorals commence on a line with the third Dorsal 

 ray : — length of fin equal to one third its height : the middle 

 rays the longest. 



The Ventrals arise just back of the pectorals ; the first ray is 

 spinous : the second ray, the longest. 



The Anal's first soft ray is equal to the length of the fin : 

 the first three rays spinous. 



The length of the Caudal fin is one third less than its height. 



The fin rays are as follows : D. 15. 15 ; P. 18 ; V. 1-5 ; A. 

 3-7 ; C. 19. 



Cryptacanthodes. Nobis. 



Generic characters. Body elongated, and very much com- 

 pressed, gradually tapering to tail, destitute of scales : head 

 broad, with no projecting spines, but the angles of the gill- 

 covers ; — the scapular and humeral spines, and the inferi- 

 or edge of the pr coper culum prominent to the touch. Nume- 

 rous depressions in frontal, suborbital', inferior maxillary and 

 preopercular bones : branchiostegous rays 7 ; mouth oblique ; 

 a single dorsal fin composed of strong spinous rays enveloped 



