FISHES OF THE GULF OF MAINE 359 



THE BLENNIES. FAMILY BLENNIID^ 



The blennies are characterized among the Gulf of Maine fishes by the location 

 of the ventrals, which are weU in front of the pectorals, combined with a single 

 dorsal fin spiny thi'oughout and running the whole length of the trunk, and with 

 an elongate and sometimes eel-like form. The only Gulf of Maine species that 

 resemble them are the wolffish and the -m-ymouth, but both of these lack ventral 

 fins, which are present in aU our blennies, though they may be very small. Fur- 

 thermore, the tremendous canine tusks and molar teeth of the wolffish (p- 370) 

 have no counterpart among the blennies, and the peculiar face of the wTymouth 

 is equally diagnostic for it (p. 368) . The eelpout (Zoarces) is also somewhat 

 blennylike in appearance, but the greater part of its dorsal fin is soft, not spiny, 

 and there is no demarkation between its anal and caudal fins. 



The blennies are a numerous tribe of carnivorous shore fishes of small size, 

 widely distributed both in northern and in tropical seas. Four species are known 

 in the Gulf of Maine. 



KEY TO GULF OF MAINE BLENNIES 



1. Ventral fins very small, less than one-fifth as long as the pectorals; a row of large 



black spots along the back extending out on the dorsal fin Rock eel, p. 359 



Ventral fins well developed, at least one-third as long as the pectoral; not black spotted 

 along the back 2 



2. More than 55 dorsal spines; body elongate, at least 8 times as' long as deep; no lateral 



line visible 3 



Less than 50 dorsal spines; body only about 7 times as long as deep-Radiated shanny, p. 366 



3. General form extremely elongate, about 15 times as long as deep; pectoral fins rounded, 



their middle rays longest Snake blenny, p. 363 



Only moderately elongate, about 8 times as long as deep; the lower rays of pectorals 

 much longer than the upper Shanny, p. 365 



138. Rock eel {Pholis gunnellus LLnnseus) 

 Butterfish; Gunnel 



Jordan and Evermann, 1896-1900, p. 2419. 



Description. — The slender flexible trunk (only about one-ninth as deep as long 

 and one-half as thick as deep), short head, and rounded nose of this little blenny 

 suggest an eel, but the spiny nature of its dorsal fin betrays its true relationship. 

 The fin (73 to 86 spines) extends from the nape back over the whole length of the 

 trunk to the base of the caudal, from which it is marked off by a shallow notch 

 only, and is of uniform height from end to end. The anal (two very short spines 

 and 37 to 44 rays) originates midway of the dorsal, to which it corresponds in height 

 and outline, and similarly runs back to meet the caudal with which it is continuous. 

 The latter fin is small and roimded. The tiny ventrals, set near together close in 

 front of the pectorals, are reduced to one very short spine and a rudimentary ray 

 each. The pectorals are smaller than in our other blennies, hardly longer than 

 the dorsal fin is high and oval in outline. The skin of the trunk is clothed with 

 very small scales, hardly visible, however, through the thick layer of slimy mucus 

 with which the rock eel is covered. The head is naked, the mouth small and set 

 102274— 25 f 24 



