180 PROCEEDINGS OF THE MALACOT.OQTCAL SOCTETT. 



NOTE ON BENSONIA MAINWA1UNGI AND MACROCHL AMI'S 

 DAZINGENSIS. 



By W. T. Blanfokd, LL.D., F.R.S. 



Bead lith December, 1900. 



When the preceding paper was first written, I included in it the 

 description of a species from the Sikhim Himalayas, which I then 

 regarded as a Bensonia, hut Col. Godwin-Austen has called my attention 

 to a Macrochlamys described by him some years ago as M. Dalingensis, and 

 to another shell which received from the late Mr. JSTevill the manuscript 

 name of Bensonia Mainwaringi. After some examination I have come 

 to the conclusion that these are either closely allied species, or sub- 

 specific races of the same species, which woidd in that case bear the 

 name Macrochlamys Mainwaringi. The following is its history. 



I obtained in 1856 at Darjiling some specimens of a shell which 

 I sent to Mr. Benson, and he returned them with the manuscript name 

 of H. ceiox. This name has already found its way into print, or 

 I would not have mentioned it. The specimens were in poor con- 

 dition, opaque and whitish, and although the shell was distinguished 

 by a peculiar character, the presence of a thickening inside the lip 

 of the aperture, and also by evidence in one rather imperfect specimen 

 that the shell continued to grow after forming a thickened lip, 

 I abstained, as Mr. Benson had done, from publishing a name on the 

 imperfect materials available for the definition of the species. My 

 friend Mr. W. Theobald (whose opinion differs from mine in many 

 matters, and amongst others concerning the publication of manuscript 

 names without a description or figure, a practice which he regards as 

 venial) included the name in a list of Himalayan Helicidae which he 

 published in 1863, and again in the list of species referred to 

 Macrochlamys in his catalogue of Land and Fresh-water Shells of 

 British India, published in 1876. 



During a latter visit to Darjiling, I think in 1870, I obtained 

 fresher specimens, but still not quite mature, of H. celox ; and a few 

 months ago. when I examined these and compared them with the 

 different species of Bensonia from the western Himalayas, it appeared 

 to me that the interest attaching to the occurrence in Sikhim of 

 what appeared to be a representative of that genus justified my 

 publishing Benson's name, now more than thirty years old, with 

 a description. So far as the shell of H celox is concerned, it exhibits 

 the peculiar character of Bensonia monticola, especially the formation 

 of a labiate aperture at different stages in the growth. I consequently 

 included a description in my paper. Fortunately delay in publication, 

 caused by my having omitted to arrange for the preparation of figures, 

 enabled me, on being shown Col. Godwin-Austen's specimens, to 

 withdraw my original paper on Bensonia, and substitute another with 

 an amended list of the species. 



