Mr. J. M. Jones on a Species of Gymnetrus. 133 



and through the spinal column, 2\ to 3 inches. (These dimensions 

 are the extreme.) 



" From the frontal extremity of the caput (excepting a slight de- 

 pression at the occiput) to the position at which the above dimen- 

 sions of depth and width were taken, a gradual elevation of the dorsal 

 ridge took place ; and from the capital portion of this ridge arose at 

 equal distances from each other a series of ten or eleven erect, quill- 

 like, flexile filaments from 2 to 3 feet in extent, gradually tapering 

 from base'to apex, and possessing, in the case of the three longest, lan- 

 ceolate points. From this series of lengthened filaments, all along 

 the back, from head to tail, extended a series of intermittent fins so 

 closely situate to each other as to present the appearance of a single 

 fin, and having the spinose rays of each individual fin joined by the 

 connecting membrane. Filaments and dorsal fin bright crimson. 

 The ventral fins were entirely destroyed, save a portion of the right 

 ventral, which is sufficient to show that it was composed of two con- 

 sistent bony rays, which probably extended some distance from the 

 body and must have formed a powerful engine of direction. The 

 pectorals were also almost entirely destroyed, although the base of 

 the right pectoral was sufficiently complete to enable me to state 

 that it contained twelve spines. Anal and caudal fins absent. 



* Head truncated, compressed ; facial outline of a dark colour. 

 Mouth so damaged as not to be positively determinable as regards 

 form and appearance, but from the portions of jaw still remaining I 

 should pronounce it malacostomous. Eyes, 14 lines in diameter, 

 slightly depressed ; irides, 3^ lines in width, of a bright silver, encir- 

 cling pupils of a somewhat oval shape, and in colour a light trans- 

 parent blue. Stomach : intestinal chamber extending from beneath 

 the gills to the anal extremity, 5 feet ; unfortunately this chamber 

 had been opened and its contents partially injured before I saw the 

 specimen, but a large portion of milt, intestine, &c. has been pre- 

 served, including the major portion of the swimming bladder, which 

 for so large a fish may be considered small ; its colour a bright 

 scarlet ; this swimming bladder contained a large amount of oily mat- 

 ter, and a piece thrown on the ruffled surface of the water imme- 

 diately stilled the agitation. Gill-rays eight in number, four to a side, 

 crimson, flabellate ; the anterior pairs furnished with double rows of 

 flabels, having the internals white, and armed on their inner side with 

 minute dart-like appendages. Gill-covers bony, radiate, not entirely 

 covering the gills. Teeth, no appearance of any. 



" In concluding the above description, I must not omit to state that 

 it was a male fish, and from the extremely fragile nature of its various 

 parts I may venture to express an opinion that it had by no means 

 attained maturity. 



" I may also remark that my measurements were taken twenty-two 

 hours after death, during which time the specimen had remained 

 exposed on the rocky shore. 



" Remarks. — This genus of Acanthopterygious fishes is of a form 

 so thin and flat in proportion to its length as to have obtained among 

 the ancient ichthyologists the name of Riband Fish. Although several 



