298 THE ZOOLOGIST. 



more acute hearing follows because of the increased size of the 

 otolith, remains to be proved. In a paper on " The Structure 

 and Functions of the Ear of the Squeteague," written by Pro- 

 fessor G-. H. Parker, Ph.D., and published in the ' Bulletin of the 

 Bureau of Fishes,' vol. xxviii. 1908, Washington, U.S.A., it seems 

 conclusively proved that in this fish the sagitta is essential to the 

 function of hearing. But, as said above, it remains to be proved 

 that better hearing follows in the case of a larger otolith. 



All the foregoing remarks have dealt with the Teleostean 

 fishes only, i. e. those having a bony skeleton. The large 

 number of Elasmobranchii have to be considered. They are 

 fishes with a cartilaginous skeleton, and do not possess solid 

 otoliths ; the place of the stone is taken by " otoconie," or ear- 

 dust. The otoconie, like the otolith, consists of crystals of 

 carbonate of lime. These cartilaginous skeletoned fishes 

 require to hear, as well as the bony framed ones. Why their 

 ear- membranes should contain dust instead of solid concretions 

 is a mystery, but the fact remains ; and in this connection it 

 should be noted that the Sturgeon (Acipenser strurio) has both 

 otoconie and otoliths in its ear-membranes. 



Only one specimen of otolith from a very deep-sea fish has 

 up to now been obtained for comment in this paper, and is shown 

 on Plate II. fig. 2. It is from the head of a Simenchelys parasiticus 

 that was obtained from a depth of seven hundred and fifty- 

 eight fathoms. The otolith, which is the left sagitta, is small for 

 the size of the fish. The right sagitta was damaged ; only a 

 fragment of it is seen. 



