LOCATION OF THE SAGCULUS IN FISHES. 145 



particular fish, the right asteriscus having been recovered, it 



only leaves the surmise that in this instance there was no left 



asteriscus. In a Platax vespertilio, one of the Chcetodontidce of 



the Indian Ocean, no lapilli could be found, although careful 



search was made. The lapillus, as a rule, is very easily got, and 



in four allied genera they were got ; it would seem that in this 



particular Platax they may have been wanting. In a Lophola- 



tilus chamaleonticeps that was most carefully dissected, the sacculi 



were got out whole ; the lagena of each showed as a distinct 



little purse, but on searching them no asteriscus could be found 



in either. There were two observers on this occasion, and had 



there been an asteriscus in either lagena it could not have 



escaped observation. In a Brosmius brosme examined, one 



lapillus, that on the left side, could not be found, the tissues 



came out whole, the " recessus utriculi " with the sacculus, and 



most careful search was made ; to judge by the right lapillus, it 



is a fair size, and could hardly have been overlooked in the 



careful search made. In two of the Characinida, a Hydrocyon 



brevis and an Alestes nurse, the rod-like sagitta was wanting in 



the first on the left side, and in the second on the right side. 



In each case the sacculus was got out whole, but no trace of 



the sagitta could be found ; the same care was exercised that 



resulted in the sagitta being found on the opposite side in each 



case. In a former paper ('Zoologist,' 1910) a note was made 



pointing out that three cases of abnormal sagitta? had been come 



across ; in these the abnormality consisted in the difference of the 



structure of the stones to what is usually the case, it would 



therefore perhaps not be assuming too much to surmise that the 



abnormal might be also met with in the guise of an otolith being 



wholly wanting. More evidence is, however, requisite in this 



matter, and it would be of interest if others who have made 



researches in otoliths would publish their experiences on the 



subject. In this connection it is interesting to note that Couch, 



in his 'Fishes of the British Islands,' vol. iv., in the article on 



the Carp, has as follows : — " Nor is this the only remarkable 



irregularity of structure, for I am informed by Edmund T. 



Higgins, Esq., who has carefully studied these objects in various 



orders of fishes, that in the Carp the otoliths (bones of the ear) 



are not always alike on both sides ; in fact, that in some in- 



