mm 



240 



Notes on some Indian and Burmese Helicidoe. 



[No. 3, 



tinguishable from recent specimens, accompany the extinct fauna 

 which embraced the Hexaprotodon and its congeners : (vide Memoirs 

 of the Geological Survey, Vol. II.) 



Of species subject to considerable local variation, Helix Huttoni 

 may be selected, if, as I am inclined to think, it may be regarded as 

 specifically identical with H. rotatoria V. dem Busch ; and the highly 

 variable H. similaris, Fer., with respect to which it may here be re- 

 marked, that its most variable and dissimilar forms, are not those most 

 widely dissociated in space, as might be surmised from the Darwinian 

 explanation for such variations, as its local Indian forms more widely 

 differ from the type and from one another, than individuals from the 

 far off Mauritius and the Brazils. 

 Helix similaris, Fer. 



At the head of the varieties, as I regard them, of this species, I 

 place II scalpturita, B. This form inhabits the Irawadi valley above 

 the British frontier, and is a stout well marked shell passing by de- 

 grees into H. Zoroaster, Th., though in this case as in others, the 

 intermediate forms are usually scarcer individually and more variable 

 than the types they tend to unite. Allied to some extent, but not 

 very closely, is H. Peguensis, 13., from I believe, the Eastern parts of 

 Pegu. H. Zoroaster which is intimately related to H. scalpturita on 

 the one hand and H. similaris on the other, occurs in tolerable num- 

 ber about Thaiet mio and the neighbourhood, and passes gradually 

 into the type form of H. similaris. II pilidion, B., is a thin-keeled 

 shell related to II similaris, from probably the same locality as H. 

 Peguensis, and last comes the rotund, globular shell common about 

 Thaiet mio, Prome, &c, described by Benson as H. lolus. Several 

 intermediate gradations occur between H. Zoroaster, H* lolus and the 

 type H. similaris, but not sufficiently marked to require special enu- 

 meration ; the whole may thus naturally be arranged as below, those 

 marked thus # being aberrant, the forms required to connect them 

 more closely, having probably to be discovered. 



II. scalpturita, B. 

 H. Peguensis, B* 

 H. Zoroaster, Ih. 

 H. pilidion, J5. # 

 II. similaris, Per. 

 II. holus, B. 

 H. cestus, B* 



Ava. 



Thaiet mio, Prome, &c. 



Thaiet mio, Bengal, Mauritius, 

 Thaiet mio, Prome, &c. 

 Khasi hills. 



