﻿MONOGIUPH OF THE ATLANTIDAE. 23 



Indian Ocean, 



February '04, 



1 



sp.. 



Buitendijk. 



» 



January '06, 



2 



sp.. 











sp., 



n 





November '06, 



1 



sp.. 



n 



» 



March '07, 



1 



sp.. 



» 



Gulf of Aden, 



December '05, 



] 



sp., 



» 





Marcli 17, '07, 



1 



sp., 



V 



Java-Sea, 



May '06, 



1 



sp., 





This species 



is very closely 



allied 



to A. 



iiijiata] the 



whorls, however, are not only fewer iu Dumber (5), but 

 the whole spire is much larger (fig. 23), the coils regularly 

 increasing iu size, and provided, nearly throughout, with a 

 very distinct spiral sculpture, consisting of 3 — 4 lines on 

 each whorl; this sculpture exists also at the under side 

 of the shell, on the penultimate whorl, where it is wholly 

 absent in A. injiata and A. depressa. It may be here once 

 more a feature, disappearing in advancing age, but even 

 then the proportion of spire aud last whorl aflfords a 

 specific distinctness. On side view (fig. 24) the spire has 

 a conical form, somewhat larger and higher than in A. 

 inflata. Aperture rather small. Shell colourless, base of the 

 keel diffusely reddish-brown, spire somewhat darker, greyish, 

 owing to the gonad of the animal, in which often, in very 

 regular distances around the suture, dark pigmented spots 

 are to be seen. 



I have scarcely any doubt, the shell', figured by Vayssiere 

 under the name of ^ A, quoyana'\ will belong to the species 

 under discussion (copied in my monograph, PI. 1, fig. 40) ; 

 though nothing is mentioned about the spiral sculpture, 

 the surface view of the shell is exactly the same. The 

 keel extends to the outer lip, but Vayssiere himself states, 

 the aperture of his specimen was damaged. 



Group of Atlanta tiirriculata. 



This group comprises two species: 

 9. Atlanta tiirriculatd d'Orbigny. 

 10. Atlanta fusca Souleyet. 



;Xotes from th.e Leyden Museum, Vol. XXX. 



