OBSERVATIONS ON THE SHELLS OF THE FAMILY DOLIID.E. 



By E. W. Vredenburg, B.L., B.Sc, Â.R.S.M., A.R.C.Sc, F.G.S., 



Superintendent, Geological Survey of India. (Communicated 



with the kind permission of the Director, Geological 



Survey of India. ) 



(With Plates II— VIII.) M^ al MB ,.- 



1. — Note on Dolium (Eudolium) fasgiatum (Bruguière), and on the 



sub-genus Eudolium. 



In Volume V of the Records of the Indian Museum (1910, p. 34), Mr. H. B. Preston 

 has figured a remarkable specimen of Dolium from Balasore Bay, characterised by the 

 presence, on the body-whorl, of a varix situated at an angular distance of about 

 35 from the thickened outer lip. The shell has been described as a new species 

 under the name of Dolium varicosum. The collections of the Indian Museum include 

 four more specimens exhibiting a similar feature : two from Hong-Kono-, one from 

 Vizagapatam, and another from the collections of the Asiatic Society, the exact 

 origin of which is unknown. As has been pointed out to me by Dr. Annandale, three 

 of these shells, including one of the Hong-Kong examples, are specimens of Dolium 

 fasciatum (Bruguière), to which species evidently belongs also the Balasore specimen 

 to which Mr. Preston has already drawn attention. The Balasore specimen had 

 long been dead at the time when it was collected, for it is greatly corroded, over- 

 grown internally as well as externally by encrusting organisms (oysters, barnacles, 

 Serpula, and polyzoa), while no trace remains of the coloured bands which form so 

 characteristic a feature of Dolium fasciatum. Amongst the four varicose speci- 

 mens of Dolium fasciatum preserved in the collection, the Balasore specimen is 

 remarkable as the smallest, measuring 57x40 mm., 1 while the dimensions of the 

 Hong-Kong specimen are 100 x74 mm., of the Vizagapatam specimen 86 x 65 mm., 

 and of the specimen of uncertain origin 82x60 mm. It should be kept in mind 

 that the three localities from which varicose specimens are known to have been 

 obtained, that is Balasore, Vizagapatam and Hong-Kong, have also yielded normal 

 specimens, and also that the latter often far exceed in size the varicose individuals. 

 For instance, one of the specimens from Balasore Bay, in which there is no super- 



1 The terminal growth of this stunted specimen is abnormal : the outer lip being posteriorly distorted so as to com- 

 municate an unusually narrow outline to the posterior part of the aperture and to the general ventral appearance of the 

 shell. This anomaly does not affect the penultimate varix which possesses the normal shape of the aperture of other 

 specimens, so that, viewed dorsally, the shell exhibits the usual globose-ovoid outline. 



