1919.] E. W Vredenbttrg : Shells of the family Doliidœ. 173 



diagnosis merges into that of Dolium ormarense. Nevertheless the prominence of the 

 spiral ornaments of the second and third order on the spire-whorls recalls Dolium 

 maculatum more than D. ormarense. This question cannot perhaps be definitely 

 settled without the discovery of better preserved specimens, especially such as might 

 exhibit the apertural characters. 



Another fossil species from the pliocene of Java, Dolium hochstetteri, Martin 

 (Samml. des geol. Reichs- Museums in Leiden, new series, Vol. I, p. 162) is perhaps 

 also to be classified in the same group with Dolium tessellatum, from which it is dis- 

 tinguished by its extremely flattened spire and the posterior inflation of the body- 

 whorl. The details of the aperture are unfortunately not known. 



Lastly, another upper tertiary fossil from the Mekran, provisionally named 

 Dolium arabicum, and probably identical with Dolium townsendi, Newton (Geol. 

 Mag., dec. 5, Vol. II, p. 301) is probably also related to Dolium costatum, with which 

 it agrees in the shape and ornamentation of the spire, but from which it differs owing 

 to the irregular distribution of the spiral ribs on the body-whorl. In this case also, 

 owing to the absence of the apertural characters, the precise affinities of the species 

 remain uncertain. 



Distribution of Dolium tessellatum and Dolium maculatum. — The areas over which 

 the two species are found at the present day are to a large extent distinct, though 

 they partly overlap. Dolium tessellatum does not seem to spread further west than 

 the eastern portion of the Bay of Bengal, nor Dolium maculatum further east than 

 the Malay Islands, while, in a westward direction, D. maculatum occurs apparently 

 throughout the Arabian Sea, and, in an eastern direction, D. tessellatum extends as 

 far as Japan. The geographical range of D. tessellatum appears to have been more 

 extensive in former geological times than at the present day, for its occurrence as a 

 fossil in the Mekran beds indicates its former presence, in later tertiary times, in 

 the area now occupied by the Arabian Sea. 



III. — The specific identity of Dolium luteostoma, Küster, with Dolium 

 variegatum, lamarck, and of dolium maonificüm, g. b. sowerby, 



with Dolium crin en se, Dillwyn. 



On a previous occasion (Journal As. Soc. Bengal, new series, Vol. XIV, 1918, 

 p. 449) I have commented upon the apparently discontinuous distribution of Dolium 

 variegatum, Lamarck, a conspicuous shell previously regarded as special to the Austra- 

 lian region, but which has now been shown to occur also in the northern part of the 

 Arabian Sea. The collections in the Indian Museum include specimens from Maskat, 

 and I have also ascertained the presence of the shell at Karachi. It was moreover 

 noticed that a shell found at Charbar on the northern shore of the Gulf of Oman, by 

 Mr. Townsend, and referred by Melvill and Standen to "Dolium galea var. luteosto- 

 mum" (Proc. Zool. Soc. London, 1901, Vol. II, p. 385), probably also represents a 

 specimen of Dolium variegatum. 



