284 MR. E. A. SMITH ON THE [Apr. I, 



no such species as L. helence occurs, nor is it enumerated by Jeffreys 

 in the list in the * Annals and Magazine of Natural History.' All 

 he says concerning it i$ that it is " a small periwinkle, found abun- 

 dantly alive and sticking to the rocks all round the sea coast at and 

 above high-water mark." 



I am inclined to believe that the shells which I have associated 

 with i. miliaris are the more common species ; but as that was the 

 only species of this genus received from Mr. Melliss, I have con- 

 cluded that his L. helence must be the little conical form described 

 above. 



It is remarkable for its elevated, straight-sided, conical spire, small 

 aperture, and angular body-whorl. The pale zone on the base is 

 situated about the middle, so that a small central portion is left of a 

 rich brown colour. The tubercles on the spire are not closely packed, 

 but are often separated by spaces wider than themselves. 



Modulus modulus, var. 



Hab. West Indies generally ; Florida for var. y^oWrfawa. 



The St. Helena specimens most closely approach that form of this 

 species which has been named M. fioridanus by Conrad. None of 

 them, however, are nearly so large as his figure (Amer. Journ. Couch, 

 vol. V. pi. xii. fig. 6). The radiating ribs are less numerous and not 

 so regular ; the spotting on the basal ribs, which are finer, is less 

 distinct, and the concentric furrow near the middle of the base, 

 which is more conspicuous than the rest, is rather more noticeable. 



The considerable variation among the specimens from St. Helena 

 has induced me to regard them as variations of this American species 

 rather than as a distinct species. Had they, on the contrary, been 

 constant in their characters, I believe enough differences might be 

 indicated to entitle them to specific rank. 



Planaxis lineatus (Da Costa). 



Hah. West Indies, St. Vincent's, Jamaica, St. Thomas, St. John's, 

 St. Martin. 



All the specimens from St. Helena are dead shells, and faded, but 

 seem to belong to this species. It was also obtained at Ascension 

 Island by Dr. Conry. A very similar species, PI. hermannseni, 

 Dunker, occurs on the West-African coast at Benguela. 



Planaxis eboreus, Smith. 



Hab. St. Thomas and St. Vincent. 



The two specimens from St. Helena agree in all respects with 

 West-Indian examples. 



The colouring of the figure of this species (Conch. Icon. vol. xx. 

 pi. V. fig. 33) is simply absurd. In the copy of the work before me 

 the entire shell is of a lemon-yellow tint, varied with a few spiral red 

 lines. All this is imaginary, as the colour is pure white, with the 

 exception of the brownish apex and the dots on the edge of the 

 iabrum. 



