THE NAUTILUS. 129 



the lateral margins are less expanded, they are nearly parallel, the 

 left being slightly convex, the right slightly concave; as usual in this 

 stage the sides of the aperture have the appearance of being drawn 

 in toward each other in the process of constructing the septum, in 

 front of the septum the anterior margin is somewhat expanded ; the 

 septum occupies about two-thirds of the entire length, it is decidedly 

 curved along the lateral margins and posteriorly, but the anterior 

 portion is flattened in the center as though from contact with the 

 back of the animal when in motion and towards the septum descends 

 quite obliquely ; the margin of the septum is only slightly convex in 

 the center, curving quite abruptly forward as it joins the lateral 

 margins of the shell. The surface conditions are as in the non- 

 septate form. 



The fully matured (Gunlachoid) stage is unknown. 

 Length 2.1, width at margin of septum 1, greatest width 1.2, alt. 

 75 mm. 



Type locality, Alexandria, Egypt. 



Types no. 35966 Coll. Walker. Cotypes in the collection of Paul 

 Pallary. 



Dr. Weber has kindly furnished outlines (figs. 15-16) of the types 

 of Bourguignat's unpublished species and there can be no question 

 but that this, and not the A. clessinianus of Jickeli, was the form that 

 he had intended to describe under the name which I have adopted. 

 It is also the species that Pallary erroneously referred to as A. 

 clessini, but did not describe. Both names being without published 

 description, I have given the preference to the anterior one of 

 Bourguignat. 



I have no doubt but that both of the forms above described belong 

 to the same species. 



The non-septate form is very similar to the North American A. 

 shimeMi Pils. and A. pumilas Sterki, but differs from both in eleva- 

 tion and other details. Dr. Pilsbry has already suggested that 

 shimekii is the non-septate form of a Gundlachia, and I am inclined 

 to think that pumilus will prove to be the corresponding condition of 

 the Ohio Gundlachia, which is probably the meekiana of Stimpson. 

 The occurrence of this species in Egypt was wholly unexpected 

 and was the first record of the genus from the Old World. 1 



1 Shortly after these shells were received from M. Pallary, I received from 



