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 heing 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 tlie gape appearing 



limited, although, as remarked by Willoughby and K.isso, 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 j^articular 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, Laccpede 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 IMontagu'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. TI. 2 G 



