﻿16 MONOGRAPH OF THE ATLANTIDAE. 



This species is to be distinguished by the inner lip and 

 the adjacent part of the last whorl not being in close 

 contact with the keel, thus showing a tendency to detorsion, 

 as this is pronounced much more clearly in Carinaria. One 

 may suppose this to be a character dependent on age, 

 but this idea is contrary to the fact that A. steindachneri 

 reaches a size of only 3 — 4 mm., whereas even the largest 

 specimens of A. peroni (10 mm.) never show a similar 

 loosing of the whorls. In all other respects (the radula of 

 A. steindachneri is not known) the two species are closely 

 connected. 



Species 3. Atlanta ajffinis Tesch. 

 1906. Atlanta a finis Tesch. 



For description and figures I refer to my monograph 

 (p. 53, PI. Vlll, figs. 9 and 10), where I have tried to 

 give a sufficient diagnosis of this species, which, like the 

 foregoing, is very closely connected with A. peroni. Besides 

 some characteristic features of the shell, I may draw 

 attention to the fact that the intermediate plate of the 

 radula does not show a small tooth at its concave, lateral 

 side, and that the lateral teeth are comparatively longer 

 than in A. peroni. 



Species 4. Atlanta gaudichaudi Souleyet. 

 1852. Atlanta gaudichaudi Souleyet. 



(Plates 1 and 2, fig. 10). 



Dry shells : 



N. Atlantic Ocean, purchased 1907, 2 sp., Sowerby and Fulton. 

 Animals: 



Red Sea, May '06, 1 sp., Buitenclijk. 



Indian Ocean, April '06, 2 sp., „ 



„ September '06, 1 sp,, „ 



,, November '06, 1 sp., „ 



Notes from the Leyden IVTuseurn, Vol. JXXX. 



