108 THE ZOOLOGIST. 



just under the forward end of a white leathery tissue forming 

 the end of the swim-bladder, where this is connected with the 

 ear labyrinth. The sacculus is embedded in a bony pocket 

 which requires cutting away. The lagena lobe of the sacculus 

 is larger than the front portion, the astericus being larger than 

 the sagitta. The lapillus, however, in this fish is the largest 

 of the three otoliths (see fig. I., 2, p. 107). The upper three are 

 from the right side of the head, the lapillus being to the left, the 

 asteriscus to the right, and the sagitta below them. The three 

 lower in the same order belong to the left side. A similar 

 system is kept to in all the other illustrations of the otolith. 

 When otoliths have been missed in dissection their place is left 

 blank. When, however, a whole side is wanting, the ear 

 labyrinth of that side has been kept for other purposes. 



NoTOPTERIDJE. 



Notopterus afer, an African fish, has very thin transparent 

 bone under the pockets in which the sacculus is contained, but 

 this is covered by a prolongation of the swim-bladder, which 

 requires to be removed to allow the sagittae to be seen. The 

 sagitta of this fish has a long spike of a projection to it ; this is 

 peculiar to the family of this fish. A complete set of the otoliths 

 of N. kapirat, an Indian fish, is shown (fig. II., 3, p. 109). 



Osteoglosshxe. 

 Osteoglossum bicirrhosum (the " Aroowana " of British Guiana) 

 has no external indication to point out the location of the 

 sacculus. It is much enclosed in bone, which has to be split up 

 and cut away to obtain the sacculus and its contents. 



Pantodontidje. 

 Pantodon buchholzi, an African fish of small size, has a fairly 

 large and solid sagitta; it is shown (fig. II., 9, p. 109). 



Chirocentridje. 

 Chirocentrus dorab, from the Indian Ocean, gives no indication 

 from the outside as to the situation of the sacculus. It is much 

 embedded in bone. 



Clupeidje. 

 Clupea harengas (the Herring) has its sacculus lying in a 

 bony pocket that has to be cut away to get the sacculus out. 



