BUTTERFLY BLENNY. 225 



P. Cocks, Esq. that it is scarcely uncommon at Falmouth. Dr. 

 Vigors, of that town, was in the possession of one which was 

 found in the empty shell of an old whelk, and which differed 

 from the usual colour of this species in being perfectly white. 



British examples have been generally of less size than those 

 of the Mediterranean, where, as Willoughby informs us, this 

 fish has been seen to exceed seven inches in length. The 

 head is large and elevated, sloping suddenly from the eyes to 

 the mouth; the lips membranous, and the gape appearino- 

 limited, although, as remarked by Willoughby and Eisso, it is 

 capable of being much expanded. The teeth are prominent 

 and in regular order, with two canine teeth bent inward in 

 each jaw. Eyes large, and high on the head; above, and a 

 little in front of each, a tendril slightly fimbriated. Cheeks 

 full. Belly protuberant. The lateral line begins at the upper 

 portion of the gills, and is bent down as it passes beyond 

 the fulness of the belly. A particular character of this fish 

 is the high elevation of the first portion of the dorsal fin, 

 which begins close behind the head, and its first ray rises 

 high beyond the membrane, as, in a less degree, do the two 

 next rays. This fin becomes much narrower at about the 

 tenth ray, from which it again becomes wider as it passes to 

 the root of the tail. The tail itself round; the ventral fins 

 with two, and, Lacepede says, three rays; anal fin from the 

 vent to the tail. 



The colour, as well of the body as the fins, is liable to 



variation, but in its perfection it has a greenish tint, sometimes 



with blue spots, and mottled with olive-colour or brown. On 



the upper part of the anterior expansion of the dorsal fin is 



a large, and usually conspicuous dark or deep blue spot, with 



a light-coloured border, which spreads from about the fifth to 



the eighth ray. Mr. Yarrell describes his example as for the 



most part brown, and, as we have already seen, the specimen 



obtained by Dr. Vigors was white. A specimen taken in the 



Isle of Man, and described in the ninth volume of the 



^'Magazine of Natural History," had the dorsal fin only slightly 



narrower in the middle. In one of Montagu's examples the 



spot on the dorsal fin was hardly visible. This dorsal fin 



numbers twenty-seven rays, pectorals twelve, anal seventeen, 



the tail twelve. 



VOL U. 2 Q 



