LOCATION OF THE SACCULUS IN FISHES. 



109 



The same with C. finta (the Twaite Shad) and C. ilisha (the 

 " Hilsa " of Bengal, but called " Pulla " in Scinde). 



SALMONiaaa. 

 Neither in Salmo salar (the Salmon) nor in S. fario (the 

 Trout) is there any external indication of the situation of the 

 otoliths. In the latter fish the pocket is open at the top, the 

 sacculus could be lifted out without trouble. In Osmerus eper- 

 lanns (the Smelt) the sacculi are covered by two little ovoid 



Fig. II. 



1. Nebeis microps. 2. Anabas scandens. 3. Notopterus kapirat. 



4. Zeus faber. 5. Erythrinus salmoneus. 6. Macrodon trahira. 



7. Plecostomus bicirrhosus. 8. Amia calva. 9. Pantodon buchholzi. 



10. balistes capriscus. 11. mormyrus kannume. 



lumps of thin bone on the under side of the basi-occiput, which 

 allow the sagittae, large for the size of the fish, to be seen.* 

 Salvelinus ivillughbii (the Charr) has no external indication of the 

 situation of the sacculi. The basi-occiput has two swellings on 

 the under side, but dissection reveals that they only cover the 

 muscle actuating the eyeball. The sacculi really lie above this 

 muscle. The cavity containing the otolith is open at the top, 

 and the sacculus can be lifted out without cutting away of bone. 



* Salmo salar and. Osmerus eperlanus are figured in 'Zoologist,' vol. xiv., 



p. 293, pi. i. 13, 14. 



(To be continued.) 



