260 HISTORY OF THE FISHES OF MASSACHUSETTS. 



GENUS III. GUNNELLUS, FLEMING. 



Body elongated, much compressed. Head oblong. Mouth small. Teeth velvet- 

 like, or in cards. Dorsal rays spinous throughout. Ventrals excessively small, and 

 reduced often to a single spine. 



GUNNELLUS MUCRONATUS, Cuv. 



The Butter-fish. 

 (PLATE XVII. FIG. 2.) 



Ophidium mucronatum, Spinous Ophidium, MITCHILL, Trans. Lit. and Phil. Soc. of N. Y., i. p. 361, pi. 1, fig. 1. 



Le Gonnelle epineux, Gunndlus mucronatus, Cuv., Cuv. et VAL., xi. p. 427. 



Blennius (Centronotus) gunndlus, LIN., Spotted Gunndle, RICH., Fauna Boreal. Americ., in. p. 91. 



Murcenoides guttata, Spotted Gunnel, LACEP., STOKER, Report, p. 65. 



Gunndlus mucronatus, American Butter-fish, DEKAY, Report, p. 153, pi. 12, fig. 36. 



" " STOKEB, Mem. Amer. Acad., New Series, n. p. 374. 



" " " Synopsis, p. 122. 



" " H. R. STOBEH, Bost. Journ. Nat. Hist., vi. p. 261. 



Color. The living fish is of an olive-brown color, with numerous transverse, indis- 

 tinct, darker bands upon the sides ; about twelve black ocelli along the base of the 

 dorsal fin, each surrounded by a yellow ring. Fins yellow; the anal barred with 

 white. Pupils black; irides golden. Abdomen yellowish. An oblique black band 

 passes from beneath the eye to the throat. 



Description. Body elongated, compressed, scaleless ; and so translucent, that when 

 the fish is held to the light, the vertebral column is distinctly seen. Head about one 

 tenth the length of the body, convex above, blunted anteriorly. Gape of mouth 

 nearly vertical. Jaws equal. Minute sharp teeth upon each jaw, and upon vomer. 



The dorsal fin, which is composed of spinous rays entirely concealed, save their 

 points, by the membrane, is but slightly raised above the back, and commences on a 

 line above the posterior angle of the operculum, and is continued nearly to the tail, 

 to which it is attached by a membrane. 



The pectorals, which are situated just beneath the posterior angle of the operculum, 

 are small and delicate. 



Two small spines, attended each by a delicate filamentous ray, directly in front of 

 the pectorals, take the place of the ventrals. 



The anal fin, which is rather higher than the dorsal, commences on the posterior 

 half of the body, and is continued nearly to the tail, to which it is attached by a 

 membrane, as the dorsal. The first two rays are spinous, the remainder flexible. 



