MONOGKAPH 01' THE ATLANTIDAE. 



21 



The shell, described by Vayssière under the name of 

 A. quoyana (copied in my monograph, PI. I, fig. 40) is 

 certainly not this species, but must be referred to A. 

 helicinoides as I shall attempt to show further on (p. 23J. 



On the other hand the latter author has designated 

 (p. 55, PI. VI, fig. 90) under the name of »A. inelinata" 

 a specimen, which in my opinion is an A. inflaia. The 

 shell, seen from apex, agrees exactly with my figure of 

 the type, with the only exceptions, that no spiral sculpture 

 is mentioned, and that the keel penetrates between the 

 penultimate whorl and the inner lip. These two features 

 may be, however, safely supposed to be dependent on age 

 (the specimen of Vayssière measured 2,6 mm.); I have 

 noted previously that the sculpture becomes less distinct 

 in larger shells. 



Another specimen of Vayssière, called also » A. incli?iata", 

 really belongs to A. fusca (see p. 26). 



Species 7. Atlanta depressa Souleyet. 



1852. Atlanta depressa Souleyet. 



1906. Atlanta rosea Tesch, non Souleyet. 



(Plates 3 and 4, figs. 18—22). 



Animals : 



Indian Ocean, January '06, 2 sp., Buitendijk. 



April '06, 1 sp., „ 



Gulf of Aden, December '05, 1 sp., „ 



The types I have studied, had unfortunately their shells 

 quite dissolved. Among the spoils of Mr. Buitendijk, however, 

 I had the good fortune to find some specimens, surely to 

 be referred to A. depressa, the typical spire of which 

 (comparatively larger than in A. injlata, compare figs. 13 and 

 18) could be detected even in the damaged type-specimens 

 of Souleyet. This species may be very easily confounded 

 with A. inflata, to which it is most nearly related, but it 

 is distinguished : 1°. by the comparatively larger spire, 



Notes from the Leyden Museum, Vol. XXX. 



