178 Memoirs of the Indian Museum. [Vol. Vil, 



p. 661) and of Oossmann (Essais de Paléoconchologie comparée, fasc. V, p. 136), the 

 Doliidse include two genera, Dolium and Pirula, while Dolium is itself divided into 

 three subgenera, namely Dolium, s. str., Eudolium and Malea. Several authors treat 

 Malea as a separate genus. 



Genus Dolium, d'Argenville, 1757. 



The species of Dolium, both fossil and recent, hitherto recorded are provisionally 

 grouped in the following list in which are included also two fossil species from the 

 Mekran district, of which the descriptions are not yet published, and which are 

 mentioned with provisional names, but which probably correspond with two species 

 which have already been named and figured. This particular question will be fully 

 discussed, it is hoped, at no very distant date in the publications of the Geological 

 Survey of India. 



The proposed limits of the subgenus Eudolium have been discussed in a fore- 

 going paper. 



The species included within the three subgenera of Dolium may be grouped in 

 the following nine divisions : 



Dolium, s. str. 



It is proposed to restrict Dolium, s. str. to those shells in which the outer lip is 

 simple or internally slightly thickened, and the columella smooth at all stages of 

 growth. 



ist Division. 



This division which may be called the group of Dolium galea (Linn.), after the 

 type of the genus, includes globose or slightly ovoid shells of large or very large size in 

 which the spiral ribs are mostly contiguous or nearly so. The following forms have 

 been recognized : — 



Dolium galea (Linn.), in which the ribs are very numerous and the sutures deeply 

 sunken. There is a marked decrease in the degree of curvature along the zone of 

 maximum width, this portion of the shell tending therefore to assume a sub -cylindri- 

 cal outline. 



Dolium variegatum, Lamarck, in which the ribs are fewer and the curvature more 

 continuous than in Dolium galea, from which it is usually distinguished also by the 

 presence of brown maculations along many of the ribs. Küster' s Dolium luteostoma 

 and Dunker's D. japonicum are synonymous. 



Dolium melanostoma, Jay, in which the number of ribs and the shape of the body- 

 whorl are about the same as in D. variegatum from which it is distinguished by its 

 more subulate spire, the feebly sunken sutures, the absence of maculations on the 

 ribs, and the dark tint of the aperture. 



Dolium chinense, Dillwyn, distinguished from D. variegatum by its smaller size, 

 more numerous and more flattened ribs, and its feebly sunken suture. Dolium 

 magnificum, G. B. Sowerby, represents the full-grown condition of this species. 



Dolium olearium,, Bruguière, which resembles Dolium variegatum in general out- 



