48 



The LisJi Naturalist. 



March, 



The spermatheca in <iacli case has been moved out of its 

 natural position to show its shape, which is different from 

 that which prevails in the L. pereger group. In the Z,. ;^/-^- 

 ienuis the female side of the epididjniis has developed to such 

 an extent as to enwrap the rest of the apparatus. In these 

 figures N indicates the nidamental gland, and S the sperma- 

 theca. 



The remaining figures (Plate 2) represent typical teeth from 

 the radulae of the species above mentioned. The general 

 aspect is ver}^ distinct in each case ; but considerations of 

 time have prevented me from giving drawings of a large 

 portion of each radula, as I had intended. These tracings of 

 typical teeth will serve to show the more striking points of 

 difference. Putting them in a tabular form, we have the 

 following comparison : — 



I have in preparation notes on the actual numbers and 

 measurements of the radular teeth of the different lyimnseas, 

 and in these the figures relating to the above species will be 

 included. 



Those who are interested in the preparation of radulae will 

 find it an advantage to try mounting in styrax, which (owing 



