222 Mr. Cosmo Melvill on the 



The upper shoulder of this new form resembles C. algo- 

 ensis (fig. 2i), with which it is of uniform size. In shape it 

 assimilates either shell ; it is not, however, deeply umbilicated, 

 as is G. capeusis, the base is white, with numerous striae, the 

 converging lins developing into fine labial teeth, two lircC 

 meeting at the tooth projection, eighteen in number, while 

 I have counted as many as twenty-five on well developed 

 C. capeusis. The columellar teeth, as in that species, are 

 represented by the fine projecting lira^ alone, thus differing 

 from all the Lnponice^ which have developed teeth on both 

 sides, with the exception of L. edentula. But the smooth 

 dorsal surface, size of the aperture, and the spotted lateral 

 margins, are as in Luponia. 



G. gangrenosa (Sol.). Reeve, Conch. Icon., pi. xviii.,. 

 f gGa. In the typical form, the tips, fuscous above, orange 

 beneath, are characteristic. 



{a)Boivijni{K.\QnQY),^g.g6b. Rientzii (Dunk.). This is 

 a large shell, dorsal surface grey, the sinus usually marked 

 by brown streak. Extremities uncolourcd. Very close to 

 erosa (L.), van a. cf. Sowb., Thes. Conch., f 232. From 

 Zanzibar. 



{b) vielanosema (var. nov.). Smaller, the extremities of 

 dorsal surface with very wide, black, suffused extension of 

 marking, sides white enamelled as far as dorsal sinus. I have 

 seen fine specimens of this in the National Collection, and in 

 that of Mr. Williams. From Mauritius. This may be what 

 Dunker intends by his var. Rientzii, but authors seem much 

 mixed in their opinions, and the name and description arc 

 hopelessly confused with Boivinii. 



C. erosa (L.). Type Reeve, Conch. Icon., pi. xi., f 43. 

 Sowerby, Thes. Conch., pi. xviii., f in — 112. There arc 

 several constant varieties of this common and well-known 

 species, the type of which may be described as follows : — 

 Shell ovate, oblong, somewhat flattened, but few specimens 

 exceeding long. r6o, lat. vi2 mm. The back buff- 



