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fins to a narrow-rayed fringe, with the first ray elongated, more or less completely 
received in a longitudinal groove. There is a band of teeth in the jaws, and another 
on the vomer, and all the species have barbels, not only on the chin, but likewise 
on the muzzle, the number of these appendages affording the readiest means of 
specific discrimination. They are all of small size, and while ranging over the 
same seas as the ling, likewise extend to those of Japan, the Cape, and New 
Zealand. The British representatives of the genus include the five-bearded 
rockling (M. mustela), with four upper barbels, the four-bearded rockling ( M. 
cimbria), and the common three-bearded rockling (M. tricirrhata) ; the little fish 
commonly known as the mackerel-midge, and formerly regarded as the representa¬ 
tive of a distinct genus being only the young of the rocklings. 
Brief mention may be made here of a fish from the Northern, Temperate, and 
Arctic seas, known as the torsk ( Brosmius bro.sme), on account of its forming the 
sole representative of a group characterised by having only a single long dorsal 
and a shorter single anal fin, the caudal being distinct, the narrow pectorals formed 
of five rays, teeth present on the vomer and palatines, as well as in the jaws, and 
the chin furnished with a barbel. Attaining a length of a little over 20 inches 
the torsk is occasionally taken in the Firth of Forth, and is abundant round the 
Shetlands and Orkneys. 
Sand-Eels and their Allies, —Family Ophidiidai. 
In this rather small family, almost all the members of which are marine, the 
pelvic fins, if developed at all, are rudimentary; there is no separate anterior dorsal 
or anterior anal, and the caudal is generally confluent with the median fins. In 
form the body is more or less elongate, but it may be either naked or scaled. 
The dorsal fin occupies the greater portion of the back; the rudimentary pelvics 
are jugular in position; the gill-openings are wide; and the gill-membranes are not 
attached to the isthmus. While some of these fishes are deep-sea forms, others are 
littoral. The family may be divided into five subfamily groups. 
The most remarkable representatives of the first subfamily (in 
Cave Fish • 
which pelvic fins, attached to the pectoral girdle, are always present) 
are two small fishes from the subterranean fresh waters of certain caves in Cuba, 
constituting the genus Lucifuga. They are totally blind, with the eyes rudi- 
mental and covered with skin, or wanting, and always live in perpetual darkness. 
The cave-fish are closely allied to certain small fishes from the Tropical Atlantic 
and Indian Oceans forming the genus Brotula, and characterised by the elongate 
body being covered with minute scales, the moderate-sized eyes, the reduction of 
each pelvic fin to a single filament, of which the extremity may be split, the 
villifonn teeth, and the presence of barbels on the muzzle; these barbels being 
reduced in the cave-fish to small tubercles. With the exception of these cave- 
fish, all the members of this family are marine forms; and it is very curious that 
among the latter there are two very rare species, respectively constituting the 
genera Typhlonus and Aphyonus, found at great depths in the southern oceans, 
which are also completely blind, and apparently unprovided with any phosphorescent 
organs. 
