FKESHWATER GASTROPODA FROM BIADAGASCAR. 381 



Shield rather large, rounded posteriorly, wrinkled and granular, with a 



small dorsal pore. Tail truncate- 

 Foot deeply sulcate transversely and its edge thrown into folds f in the 



posterior region. Anteriorly smooth and non-plicate. The median third 



about equals the lateral areas in width. 



Colour (in alcohol) : very pale dirty yellow, with two lateral bands of 



faint purplish-brown on the shield. 



Length 25'5 mm., breadth 9 mm. Breadth of foot 4=5 mm. 

 Holoty|)e in the Zoological Department, British Museum. 



Fam. ZoNiTiD^. 



19. *E.HYSOTA ^QUivocA, n. sp. (Plate 35. figs. 16-18.) 



Woods, liassic limestone, Ambongo. 



The above generic position has been assigned upon the conchological 

 characters specified as generic by Pilsbry (Man. Conch. 2nd series, ii. p. 6), 

 though it is highly probable that more complete anatomical knowledge of the 

 group will lead to a redistribution of the forms assigned to this and the 

 related genera. 



Shell very depressed ; spire scarcely salient at all, perforate, shouldered at 

 the beginning of the last whorl ; whorls 5^, gradually increasing in size, the 

 last increasing rapidly. The sculpture is the same above and below, and 

 consists of closely-set and slightly undulating lines of growth finely decussated 

 to give a close granular texture to the surface. Suture impressed. Aperture 

 irregularly lunate, the inferior edge sloping gently down to an expansion 

 occupying the extreme inferior angle ; external superior angle rounded off; 

 columellar lip slightly expanded over the umbilicus. Peristome a little 

 thickened. Colour very pale dirty yellow, becoming brighter at the peri- 

 stome and paler in the columellar region. 



Dimensions (max.) 35"5 mm. diam. x 16 mm. alt. 



Holotype from Ambongo, in the Zoological Department, British Museum. 



20. *Kalidos Bournki, n. sp. (Plate 35. figs. 8-10,) 



Woods, on limestone soil, " Turingy de Namoroko, Ambongo" (P. de 

 la B.). 



This is clearly to be included in the genus proposed by Gude (Proc. Malac. 

 Soc. 1911, p. 27o) for Helix ekongoensis, Angas. At first sight it appears to 

 resemble that species ; but while ekongoensis is obviously juvenile, and this 

 species is adult, the latter is smaller, while, in addition, it lacks the exquisite 

 sculpture of Angas's species, is flatter in the spire, and exhibits other 

 differences. 



t It is just possible, but not at all likely, that this plication is due to contraction 

 in spirit. 



