BUTTERFLY BLENNT. 
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 appearing 
limited, although, as remarked by Willoughby and Bisso, 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 Avith 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 broAvn, 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 tall tAvelve. 
YOL II. 2 G 
