FAMILY GOBID.E. Ii53 



GENUS GUNNELLUS. Cuvier. 



Body elongated, much compressed. Head ohlong. Mouth small. Teeth velvet-like, or in 

 cards. Dorsal rays spinous throughout. Ventrals excessively small, and reduced often 

 to a single spine. 



Obs. This genus was first named Centronotus by Bloch, but this name has been appHed 

 by Lacepede to another group among the Scombridje. Some EngHsh ichthyologists have con- 

 tinued to use the badly characterized genus Mureiioides of Lacepede, without being aware, 

 that while he retained the gunnellus of Linneus, he formed his new genus out of the B. 

 murenoides of Sujcf, not knowing that the two species were identical. 



THE AMERICAN BUTTER-FISH. 



Glnneixcs MUCRONATUS. 



PLATE XII. FIG. 36. — (STATE COLLECTION.) 



Ophidium mucronatum. MiTCHiLL, Lit. and Phil. Soc. Vol. I, p. 249, pi. 2, fig. I. 

 Gunnellus mucronatus, Lf Gonelle epineux. Cov, et ViL. Hist, ties Poiss. Vol. 11, p. 247. 

 Blennius {Centronotus) gjttmelhis. RicH.\RDSON, F. B. A. Fishes, Vol. 3, p. 91. 

 Murenoides guttata, The Spotted Gunnel. StorER, Mass. Report, p. 65. 



Characteristics. Greyish, with a scries of dusky oval rings along the sides. Dorsal not united 

 to the caudal. Two sliort spines in place of the ventrals. Length four 

 to seven inches. 



Descriptioii. Body elongate, linear, much compressed. No scales could be detected with 

 a strong lens ; nor could I discover, in several specimens, any traces of a lateral line. Head 

 small, subcarinate above ; its length as one to nine compared with the total length. Mouth 

 nearly vertical. Teeth acute, distant in both jaws, and a small group on the vomer ; lower 

 jaw, when extended, longest. Branchial rays six, with a large branchial aperture. Body 

 covered with a thick coating of mucus of the consistence of butter, from which is derived 

 its popular name. 



The dorsal fin single, long, subequal, commencing above the branchial aperture, and ex- 

 tending nearly to the base of the caudal ; is composed of a very thick membrane, supported 

 by from seventy-five to seventy-eight sharp spinous rays. The pectorals rounded and feeble. 

 Beneath these, and slightly in advance, are two short and sharp spines, occupying the place 

 of ventrals. The anal fin is nearly equal throughout its whole extent, not a.s high as the 

 dorsal : it approaches still nearer to the caudal than the upper vertical tin, Init is not con- 

 nected with it. The two anterior rays are short acute spines, the remainder soft and llexil)le. 

 Caudal fin rounded. 



Fauna — Part 4. 20 



