ICHTHYOLOGY. 213 



Dorsal spines weak, and twice as lon^^ as tlie rays. Caudal wedge-shaped. Colour 

 f^rcyisli, darkened with green, on the back, and wliite on the belly. Vertical wliite. 

 Outer edges of tins sometimes dark. Grows to 2 feet in length. 



Coasts of India and Burma. 



S. coiTOR, Ham. Bueh. 



Johniiis coitor. 



Nga-ta-dum, and Nga-pok-theng. 



B. vii.; D. 10^V--v; p. 17; V. i; A. f ; C. 17. 



One central and two lateral orifices below the symphysis of the mandible. 

 Snout prominent and swollen superiorly; ujiper jaw somewhat the longer. Dorsal 

 spines weak, the second to the fourth longest. Caudal wcdge-sha])iMl. Silvery shot 

 with gold and purple. Upper lialf of first dorsal blackish. Soft dorsal, caudal and 

 anal dark externally, and a daik basal band on the anal. Grows to a foot. 



Inhabits the larger rivers of India and Burma, descending to the sea at certain 

 seasons. 



S. DiACANTinjs, Lacep. 



Johnius diacanthus and chiptis. 



B. vii.; D. 10 ^s-J-n-*; P- 18-19; V. A; A. |; C. 17. 



Upper jaw a little the longer. Five open pores under the symphysis of the 

 mandible. Dorsal spines weak, increasing to the third and fourth. Caudal wedge- 

 shaped. Brownish grey, shot with silver along the back, and fading below the 

 lateral line to silvery grey. Head glossed with purple. I'ins yellowish, with bhick 

 dots. Eyes golden. Grows to 5 feet in length. 



Burma, ascending rivers. 



This is one of the fishes which Mason describes as yioliling isinglass. 



S. AN'iors, Bloch. 



Chal-burn-dah. Andamans. 



B. vii.; D. lO^^rhfT; P. 18; V. i ; A. f; C. 17. 



Snout not overhanging, and with a small pore ou either side just above the 

 free edge of the skin. Mandible slightly advanced, with a small open pore on eitlier 

 side of the symphysis. Caudal squarish. Colour silvery-grey, white on the belly. 

 First dorsal black-tipped, or stained with grey. Second dorsal greyish. Pectoral, 

 ventral, and anal fins yellowish. Air-vessel oval, extending the whole length of the 

 belly, but yields an inferior isinglass. 



The Andamans, where not rare. 



B. Xo row of enlarged teeth in the mandible. 

 S. GLAUCus, Day. 

 B. -sii.; D. 10 ,^3o ; P. 16; V. i; A. f; C. 17. 



Snout rounded and overhanging. Snout with three pores across its base, and five 

 along its free border, which has a distinct lateral lobe. Five open pores lielow the 

 mandibular symphysis. Caudal rounded. Colour greyish-green on the back, silvery 

 below, and fine brown spots everywhere. A diffused bluish blotch on the opercles, 

 a dark spot at the base of the pectoral. First dorsal black, second dorsal, caudal, ancl 

 List half of pectoral profusely clouded with brown spots. Scales ctenoid, except on 

 mouth and cheeks. Grows to a largo size. 



The Andamans. 



S. CAHUTTA, Bloch. 



B. vii.; D. 10 ^Vt; p. 17; V. ^; A. f; C. 17. 



Colour- purplish brown, becoming golden below, paler along the lateral line. 

 Head glossed with purple. Scales cycloid, except a few between the pectoral fin and 

 lateral line. Grows to nearly a foot. 



