AVEEB : ON THE GENUS MAEI^LLA. 155 



EXPLANATION OF PLATE IX. 



Fig. 1. Maricslla Dussumieri (Valenc. MS.) Gray, after preservation in Formalde- 

 hyde, seen from the right side, and showing the right mantle keel with 

 the scar above it. 



,, la. The same, seen from above. The median mantle keel is visible, and in its 

 entirety, while the hinder end of the left one, which here follows the 

 outline of the animal, is just visible. 



,, 2. The shell ( x 2), seen from above. 



, , 2a. The same ( x 2) , seen from the left side. 



,, 3. The jaw : much enlarged. 



,, 4. The central and two adjacent lateral teeth from the radula: much enlarged. 



,, 4a. Three marginal teeth : much enlarged. 



,, 5. The genitalia ( X 2). 



,, 6. A spermatophore : greatly enlarged. 



,, 7. Genitalia, oi Mar icella Beddomei, G.- A.: somewhat enlarged. 



