OF CONCHOLOGY. 37 



ON LINGUAL DENTITION STUDIED BY THE MICROSCOPE 

 AND PHOTOGRAPHY. 



BY W. G. BINNEY. 



With Note by Thomas Bland. 



Plate il. 



Through the kindness of Mr. Sam. Powell, I was enabled, 

 during a recent visit to Newport, to study in a most satisfactory 

 way the lingual dentition of many species of terrestrial mollusks. 

 The method adopted by Mr. Powell is to use the microscope 

 together with the photograph. The result is extremely gratify- 

 ing. The picture obtained fixes forever the character of the 

 dentition and enables us to study it at our leisure. It also re- 

 moves all the uncertainty of the ordinary figures, for we have 

 the actual photograph instead of a representation of the teeth 

 as they appear to an observer. This latter point is of extreme 

 value now that it has been shown how little reliance can be 

 placed on many of the published figures of lingual dentition. 



I do not propose at this time to speak of the method employed 

 in taking the photographs. That is well understood by the 

 microscopist and photographer. My intention is simply to call 

 attention to the subject, and suggest a very satisfactory way of 

 pursuing a very difficult study. I will add, however, tliat by 

 using the negatives with the magic lantern, a still more valuable 

 method is obtained. 



The specimens figured were loaned me by Mr. Bland. Fig. 1 

 represents a portion of the lingual membrane of Pupa palanga, 

 showing one-half of several transverse series of teeth. 



Fig. 2 shows the jaw of Cylindrella rosea. It will be observed 

 that the edges are in places folded over. 



Note. — The objects shown in the accompanying figures are 

 extremely interesting, not only in themselves, but as evidence 



