126 G. Nevill — New or little-known [No. 3, 



this region, presents several points of greater probability judging from the 

 character of the existing landshells, and I would question the former 

 immediate land connection with the Indian Peninsula. I think I can point 

 out several remarkable features, which tend to show that this archipelago 

 probably received its Mollusca rather by a close connection with the 

 Nicobars, Sumatra, Java, &c, and thus of course with the Malayan Penin- 

 sula. It is scarcely necessary for me to mention that the Mollusca of 

 the Madagascar and Mascarene province give no support to the theory of 

 an ancient emigration from Europe, so few fossil landshells of pretertiary 

 times being known ; the entire absence of the genus Helicina from the ter- 

 tiary deposits of Europe as also from India proper and Ceylon at the 

 present time, I consider very significant, as the genus from its well-marked 

 characters, its robust substance, and local abundance could hardly have 

 escaped attention. I showed in 1869 that the Seychelles possess a 

 species ( H. theobaldiana, Nevill) only just separable from others found 

 in the Nicobars and adjoining Islands ; M. Morelet again has lately 

 described a most remarkable extinct subfossil form from Mauritius as 

 Helicina undulata : this species is closely allied to the Trochatella 

 mouhoti of Pfeiffer from Cambodia, which, Dr. Dohrn has justly shown, 

 cannot be classed with the West Indian species of Trochatella, but must be 

 referred to Helicina ; for these two species I suggest the new subgeneric 

 division JPseudotrochatella ; the group has its nearest known allies in 

 some Philippine forms. It will be important to endeavour to find out 

 whether there are any fossil or subfossil forms of Helicina to be found 

 in Madagascar itself. The remarkable " Malagash" section of Megalomas- 

 toma, called Hainesia by Pfeifi'er (= Mascaria, Angas), seems to me much 

 more closely allied to the Malayan and Philippine section Coptocheilus 

 of Gould than with the extinct European Tertiary forms. 



Omplialotropis is undoubtedly a most significant feature of the shell- 

 fauna of the Mascarene Islands, the genus not being known from Mada- 

 gascar, the Comoro, or Seychelle Islands ; it has also never been established 

 as found fossil in Europe, or living in India or Ceylon; there is, however, 

 one tertiary fossil to which I would call the attention of conchologists — 

 the Gardiostoma trochulus of Sandberger (' Vorwelt,' pi. XII, fig. 8), 

 which I consider perhaps referable to Omplialotropis ? Besides the Mas- 

 carene Group, the genus is found in great abundance and variety in the 

 Polynesian Archipelago and can, according to my theory, be fairly traced 

 from the one region to the other. Excluding the allied New-Zealand 

 genus Bealea, several species have been described from New Caledonia, 

 one from the Solomon Islands, two from Ceram, one from Shanghai, 

 one (O. strictus of Gould from the Loo Choo Islands) has been lately re- 

 discovered by Surgeon-Major R. Hungerford at Hongkong living on stone 



