708 SURGEON F. DAY ON THE [DeC. 5, 



the Punjaub and Burmah. Arius munillensis, Cuv. et Val., may, 

 however, belong to the genus, although, as its specific name implies, 

 it is stated to have come from Manilla. 



Genus Arius. 



In the species of this genus which I have examined the air-vessel 

 is enclosed in bone ; but a short time since the following remark by 

 Dr. Taylor of Dacca, published in the ' Gleanings in Science' (vol. ii. 

 1830), made me desirous to obtain A. y agora before I completed 

 this paper ; this I have now accomplished. Dr. Taylor observes, 

 " in the Pimelodus gagora there are two air-vessels, lodged one on 

 each side in an osseous cup, attached by a narrow neck to the body 

 of the first vertebra, close to its junction with the cranium." He 

 goes on to describe what he found ; but it could not have been in 

 Arius gagora, H. B. In Owen's 'Comparative Anatomy' (vol. i. 

 p. 491) it is stated of the air-bladder of fishes that it is "seldom 

 divided lengthwise into two bladders (Arius gagora, Polypterus, Le- 

 pidosiren, fig. 324)." 



Arius gagora, Ham. Buch. pi. 10. f. 54. 



Air-vessel large and somewhat heart-shaped, with a moderately 

 thick external fibrous coat. On removing its front wall a longitu- 

 dinal partition becomes apparent, but is not extended to its ante- 

 rior portion. It has three transverse subdivisions, forming it into 

 five cavities, owing to the longitudinal partition commencing at 

 the first transverse subdivision. These lateral cavities freely com- 

 municate with one another on the same side, and with the opposite 

 ones by means of the anterior chamber, which does not possess any 

 subdivision. 



This is the only species of the genus which I have found in fresh 

 water high up rivers, having taken it at Mandalay in Native Burmah, 

 about 650 miles from the sea. 



Arius jatius. 



Pimelodus jatius, H. B. 



Amongst many specimens that I have obtained in Calcutta this 

 year the anal rays were nineteen or twenty ; and I can indorse Ha- 

 milton Buchanan's and Mr. Blyth's observations as to the difficulty 

 of seeing the granular palatine teeth. I believe, from the descrip- 

 tion, that A. macracanthus, Giinther, reputed to have been obtained 

 from Siam, is this species. 



Arius sona. 



Pimelodus sona, H. B., appears to be the Bagrus gagorides, Cuv. 

 et Val. 



Arius nenga. 



Pimelodus nenga, H. B. (MS. figure), appears to be the Bagrus 

 arioides, Cuv. et Val. 



