1920.] S. L. HoRA : Indian Homalopteridae. 209 



to see the nature of the air-bladder, which in the genus shows 

 progressive degeneration from the normal type. Indeed even in 

 these two specimens it shows a marked difference. In specimen 

 (No. 1098) the air-bladder is very much reduced. The essentials 

 of a normal Cyprinid t5'pe are retained, though they are not well 

 marked. The posterior chamber is relatively small, while the 

 anterior one is covered by thick fibrous tissue. The coating of 

 fibrous tissue is incomplete anteriorl}^ where the bladder abuts 

 against the platform formed b}^ the transverse processes of the 

 second vertebra, while posteriorly it admits the passage to the 

 posterior chamber of the bladder. The transverse processes of the 

 second vertebra show a marked expansion near their vertebral 

 ends, much as was noticed in describing the air-bladder of Balitora 

 brucei, but in that species the vessel is not covered by a fibrous 



Fig. 3— Moditicalions of the air-bladder in the genus Psilorliynclms. 



1. Air-bladder of PsilorJijmcJiiis sp. (juv.) X 8. 



2. Air-bladder of Psilorliynchus balitora, specimen Cat. No. 940. 



X 8. 

 ,^. Air-bladder of Psilorlivncliiis balitora, specimen No. 1098, 

 (magnified). 

 a.c.=:anterior chamber; /».c.=posterior chamber; w.?w.=\ertebral modi- 

 fications. 



tissue but by a bony capsule. In B. hrucei, moreover, the posterior 

 chamber of the vessel is absent and the anterior one is divided 

 into two lateral chambers which show a tendency to separate 

 from one another. 



In the second specimen (Cat. No. 940.) the air-bladder .is 

 comparativeh' large and is apparently not covered b}' a thick 

 coat of fibrous tissue. In this case both the chambers are well- 

 developed, but the posterior one seems to have been pushed out 

 of its place during development and comes to lie against the 

 anterior chamber on the left side partly covered by it. The 

 anterior end of the bladder abuts against the specialh^ modified 

 transverse processes of the second vertebra. As the specimen 

 was already opened, I cannot be certain about the exact nature 

 of the covering of the air-bladder in this case ; but the two speci- 

 mens, between which there is no reason to suspect any specific 



