TEE "ASTEBISCUS U IN FISHES. 6i 



water, for those two fishes do the same. The Carp family have 

 their auditory organs in connection with their air-bladders, but 

 so have several of the Clupeidce, e. g. t the Herring (Clupea 

 harengus) and the Pilchard (Clupea pilchardus) f these have the 

 sagitta as the largest otolith. Certain also of the Serranida 

 (Perch family), Sparidce (Sea-Bream family), and Gadidce (Cod 

 family)* have a connection between the air-bladder and the 

 auditory organs ; all these families have the sagitta as the 

 biggest otolith. True, they have the connection between the 

 air-bladder and the auditory organs arranged on a different plan 

 to that adopted in the anatomy of the Carps, but are mentioned 

 to show that it is not due simply to the fact of their air-bladder 

 and auditory system being connected that makes the arrange- 

 ment necessary to increase the size of the asteriscus. Again, 

 the Siluridcs, which have the same method of connecting the 

 air-bladder with the auditory organs, as in the Cyprinidce, viz. 

 by a series of movably connected ossicles, have the " lapillus " 

 as their largest otolith (see note ante) ; their asteriscus, though 

 well developed, is relatively small compared to that in the Carp 

 family. A point of resemblance in these two families is that 

 each has a rod-like sagitta. 



The asteriscus of the more strictly Gadus branch of the 

 Gadidce (the Cod family) differs materially in shape from that in 

 other Teleostean fishes, as exemplified by No. 17 (the Whiting- 

 pout) ; the same stone, No. 16 (the Hake), classed with the 

 Gadidce, is much the same as the other fish examples shown, its 

 resemblance to Venetian glass having already been noted.! 



One characteristic of the shape of the asterisci that seems 

 to be common to a great many families is the little spike that 

 projects from the middle of one side ; it is apparent in sixteen 

 out of the twenty-five figured. It is so delicate as to be very 

 easily broken when dissecting this stone out of the ear-mem- 

 branes. 



Upon what are the actual uses of the otoliths in the working 

 life of Teleostean fishes authorities are not agreed. The older 



* Vide ' The Cambridge Natural History,' vol. vii. p. 389, quoting Bridge, 

 Eidewood, E. H. Weber, and Bridge and Haddon. 



f The sagitta in the Hake, a long thin stone, is also markedly different 

 to that of tbe true Gadidce. which have a solid thick stone. 



