32 



fish, has satisfied me that these differences are not of exceptionable, but 

 usual occurrence. 



The otolith of thc^ sole {Solea vulgaris) is thick and short, it is 

 without any sculptured markings, and is cuirass shaped, not unlike one 

 of the plaices' otoliths, cut in a curve across the middle. 



Tlie lemon sole {Solea ■pegusa) has this bone more circular, and of 

 almost twice the thickness. On either side of the curved end are two 

 deep ^vl■iukles, which arc entirely wanting in the other species. 



That nondescript, or rather nonplaceable creature, the eel, has small 

 otoliths, as wo shouhl expect, from the head. Tliey are very like those 

 of the flat-fishes, but curved inwards, their shape is oblong with the 

 corners rounded. 



In the fresh-water fishes of our streams, another arrangement takes 

 place altogether ; indeed I am not sure whether or not a second otolith is 

 part of the economy of hearing as well as the bone I have now described, 

 but my oppoitunities of investigating these fishes have been but 

 slight, depending indued upon my friend Mr. 0. A. Briggs, formerly of 

 Folkestone, but now of Leatherhcad, to whom I am indebted for nearly all 

 my specimens. In these fishes the otoliths are mostly of an irregular cir- 

 cular shape, they differ from those already mentioned considerably, for 

 instead of a simple denticulated edge, the rugose markings assume a distinct 

 and regular series of convolutions on er the body of the otolith, so like our 

 outward ear that they arc no doubt instituted for the same purpose, viz : 

 the collecting and retaining sound. [Several of these are figured in the 

 plate which accompanies this paper. 



I have not found otoliths amongst the cartilaginous fishes, or amongst 

 those whose skull is of a cartilaginous nature. Of the former of these 

 the skates and dog-fishes are well known examples, whilst the Doree 

 will represent the latter. The enveloping medium which takes the place 

 of a true skull in these fishes, is of great thickness of a necessity, to 

 compensate for the loss of the bone, whilst the cavity within is small in 

 proportion. Doubtless it is there in some shape, although at present it 

 has escaped me, for the dog-fish has the reputation of some sagacity which 

 pre-supposes the power of hearing. 



Apart from their connection with the fish itself, I am not aware of 

 any inherent quality, either for use or mischief, that may attach to these 

 bones, excepting as the playthings we used them for when children, but 

 formerly many objects were considered to have virtues which arc not now 

 assigned to them, and the otoliths uf the cod-fish crushed to powder were 

 at one time thought to possess curative powers, and as such were eagerly 

 sought after by persons afflicted with* calculus. 



Although I could carry my examples of variation of these bones 

 amongst kindred fishes much further, I have sufficiently proved the 

 argument with which I started, that an investigation of them will 

 not only be of use in enabling us to clear up such doubts affecting 



