1881.] Mollusca of the Indo-Malayan Fauna. 151 



than at base, the last three whorls closely, acutely, spirally striated, striau 

 slightly undulating, the interstices obliquely, longitudinally and more or 

 less subobsoletely striated, the penultimate whorl is acutely keeled in the 

 middle and again quite at its base, the last whorl is prominently carinate 

 at the periphery with a second keel halt' way between it and the suture 

 and a third round the umbilicus, the umbilical area being spirally and irre- 

 gularly keeled ; aperture rather oblique, nearly circular, peristome reflected, 

 above peculiarly and markedly sinuate, the inflection (or " sinus") broad 

 and shallow and at some slight distance from the body whorl, afterwards 

 boldly rounded, columellar margin only slightly reflected above over the 

 umbilicus, oblique, acutely angulate at base. 



Measurements of another, rather smaller specimen than the type, 

 Alt. 26, diam. 26| mil. 



As 1 have already remarked, a close ally of G. carinatum, Born (= G. 

 tricar inatum, Sow., not H. tricarinata, Miiller = G. tricarinatum, Lam., 

 a quite different species from Madagascar) ; it can, however, be always 

 easily distinguished by the more produced spire, much narrower umbilicus 

 (which is more irregularly keeled), the "fimbriate" suture (as in G. lienardi, 

 Morelet and G. Jimbriatum, Lam.), the prominent aud close-set spiral 

 striation, &c. The figures in Born, Sowerby, and Reeve all depict the true 

 C. carinatum, of which I consider Reeve's figure of G. unicolor, Pf'r. as a 

 mere variety. The Museum is indebted for two specimens of this latter form 

 to Mr. J. Caldwell, who informs me that one of his specimens of typical 

 G. carinatum was found by him with the animal still preserved and only 

 recently dead. 



Pfeiffer's figures in the Conch.-Cab. IT, pi. 89, figs. 5 to 7, as " G. 

 unicolor" represent a quite distinct species, (though also from Mauritius), 

 as can be seen by a reference to his original description, " anfr. ult\ superne 

 et medio acute carinatus," borne out by Reeve's figure of the type specimen. 

 I presume a similar confusion has arisen to that which I have explained 

 with regard to the Nanina petrosa of Hutton and again with the Htlicarion 

 inonticola of Pfeiffer (compare Moll. Yarkand Mission, page 15). 



Probably Dr. Pfeiffer rightly supposed that he had erred in describing 

 a mere variety of G. carinatum, Born, as a new species (G. unicolor) ; later 

 on, finding an allied, but very distinct, species, he figured the latter in the 

 Conch.-Cab., giving it the name of his former spurious species. 



G. caldwellianum occurs abundantly, in a subfossil state, on the 

 ascent of the Pouce Mountain, together with other extinct species of 

 Tropidoplwra and Omphalotropis. 



Type, Indian Museum; also in coll. J. Caldwell. 



