62 



THE ZOOLOGIST. 



Pagellus centrodontus. 



men of science saw in them only a means of increasing the 

 sound vibrations, and so making the hearing of the fish more 

 acute. Some modern authorities seem to see in them only an 

 organ to enable the fish to retain its equilibrium in the water, 

 and point to cases where, when the otoliths have been removed, 

 together with the semicircular canals, the fish has not been 

 able to remain in its usual vertical position. Others, and 

 possibly more correctly, credit the otoliths with the dual func- 

 tions of helping the equilibrium, as well as assisting the hearing. 

 Why three on each side of the head are needed no one has 



attempted to explain. 

 But whatever their office 

 is, it is clearly very im- 

 portant when one sees 

 the number of nerve fila- 

 ments spread over the 

 sacculus, and also that 

 7**? end of it called the la- 

 gena, showing that the 

 asteriscus carries on its 

 full share of the work 

 done by the otoliths. The 

 accompanying drawing, 

 reduced from the first- 

 ly '^ mentioned work of Gus- 

 her Retzius. taf Eetzius, depicting the 



A. asteriscus : S. sagitta : I. lagena ; s. sacculus; auditory Organs of a 

 rl. Ramulus lagerice ; rs. Hamulus sacculi. ,, _. .,. 7 ,, 



" Pagellus centrodontus 



(a sea-water Bream), shows the situation of the nerves. It may 

 be taken as fairly typical. It shows the asteriscus and nerve, 

 the Ramulus lagena, or the Branch of the lagena, spread root- 

 like over the outer surface of the lagena, just over the place 

 where the asteriscus is situated. 



In concluding this article, the assistance received, given by 

 the courtesy and liberality of the administration of the ' Stazione 

 Zoologica,' Naples, must be recorded ; without it many of the 

 specimens here shown could not have been brought to the notice 

 of the reader. 



*r 



UL. 



*5!. 



