Dr. A. Giiiither on the British Chairs. 233 



teen on each palatine bone, and six pairs on the tongue. Opei'culum 

 obtusely rounded behind, its length being two-thirds of its height ; 

 the suboperculum projects but little beyond the hind margin of the 

 opercle, its vertical width being one-half of that of the operculum. 



D. 13. A. 12. P. 13. V. 10. 



The origin of the dorsal fin is a little nearer to the end of the 

 snout than to the root of the caudal ; the length of its base is one- 

 third more than that of its last ray, and contained once and a fourth 

 in that of the fourth ray. The fifth and sixth rays form an acute 

 point, and the upper margin of the fin is straight. The first ray is 

 rudimentary, the second half the length of the third, the third two- 

 fifths the length of the fourth, the fifth simple, the sixth branched, 

 the last split to the base. The distance of the adipous fin from the 

 dorsal is but little more than twice the base of the latter. 



The origin of the anal fin is exactly in the middle between the root 

 of the caudal and that of the outer ventral ray ; the length of its 

 base is somewhat less than that of the dorsal, and is contained once 

 and a fourth in the length of the fifth ray. 



Caudal fin forked, one of the middle rays being two-fifths as long 

 as the outer ones, the length of which is contained six times and a 

 half in the total ; lobes pointed. 



The base of the pectoral is entirely free, and not overlapped by the 

 gill-cover apparatus ; it terminates at a considerable distance from 

 the vertical from the origin of the dorsal, equals the length of the 

 head without snout, and is contained once and a third in the distance 

 between its root and that of the ventral. 



The ventral is inserted beloio the middle of the dorsal. 



A specimen, 12 inches long, from the same locality, agrees very 

 well with the one first described ; its operculum, however, is as long 

 as high, and the length of the pectoral fin is nearly one-half of the 

 distance between its root and that of the ventral. 



An immature specimen, 10 inches long, differs widely from the 

 preceding, its body and its head being much more elongate. The 

 length of the head is more than the height of the body, the 

 former being one-fifth, the latter one-sixth of the total length ; the 

 operculum is longer than high, and the height of the head above the 

 mandibulary joint is less than the distance between the posterior 

 margin of the orbit and the end of the operculum ; the maxillary ex- 

 tends nearly to the vertical from the hind margin of the orbit. The 

 length of the pectoral fin is considerably less than one-half of the 

 distance between its root and that of the ventral. 



"With regard to the coloration, this species does not differ from 

 S. Willughbii ; the immature specimen has the sides silvery, and the 

 red of the lower parts is replaced by a slight tinge of orange-colour. 



Some of the specimens from Quickjock had the stomach filled with 

 food, which consisted of specimens of small species of Planorbis and 

 LimncEa, of EphemeridcB, of the larvae of LibeUula, and of small 

 fresh-water Crustacea. The number of pyloric appendages is forty- 

 four. 



Ann. ^ Mag. N. Hist. Ser. 3. Vol xii. ]6 



