SAINT HELENA, 651 



living example which was secured by Mr. P. Whitehead in an 

 immediately adjoining locality sufficed abundantly to indicate 

 the modus vivendi of the species, it having been taken at the 

 roots of one of the damp masses of intermingled moss and grass 

 which pad the base of the perpendicular rocks formed by the 

 excavation of what is known as the ' Cabbage-Tree Eoad.' There 

 can be little doubt, consequently, that the S. melanioides will 

 be ascertained to occur in humid places generally along the 

 northern slopes of the ridge below Diana's Peak. 



The numerous volutions and elongate-conical outline of this 

 fine species, added to its close and sharp longitudinal costate- 

 strise, and the obscure keel which is usually more or less trace- 

 able immediately above the aperture on the circumference of 

 the basal whorl, appear to me to bespeak its affinity with the 

 widely spread forms around the Bulimus octonus, Chemn. (now 

 usually regarded as pertaining to the genus, or section, Subu- 

 Una), particularly perhaps to the West African S. Fra&eri, Pfr., 

 and elavata, Gray ; and I think that these same characters are 

 equally suggestive of the fact, that it cannot be very remote 

 from the (nevertheless exceedingly distinct) St.-Helenian sub- 

 plicata and terebellum of Sowerby, which have been observed 

 hitherto only in a subfossil condition, and which have been re- 

 ferred by some authors to Bulimus and by others to Achatina 

 (the late Prof. Forbes indeed having, in the same paper, assigned 

 them, totidem verbis, to both 7) 1 



This singular shell has something about it which calls to 

 mind at first sight certain members of the genus Melania, its 

 dark, rich, reddish-brown hue and nearly opake surface, which 

 is more or less marbled with irregular, frequently subconfluent, 

 longitudinal ochreous streaks, in conjunction with the oblique 

 and remote, posteriorly-evanescent, obtuse, ridge-like nodules 

 which (although occasionally not very prominent) undulate the 

 anterior zone of each volution, and cause the very deeply im- 

 pressed suture to be more or less waved, or scooped-out at 

 regular intervals, giving it a character which it is impossible 

 to mistake. However few, or however numerous, the yellow 

 streaks may be, these oblique, short, posteriorly- evanescent, 

 nodiform humps are themselves always more or less yellow, or 

 ochreous ; and, when accurately inspected, there will usually be 

 seen to be a few obsolete traces of some very indistinct spiral 

 lines (decussating the closely-set longitudinal ridges) on certain 

 of the whorls. 



1 4s a not unnatural result of this indecision, the S. subplicata, Sow., is 

 cited twice over in Mr. Melliss's catalogue, first as a Bulimus, and afterwards 

 as an Achatina, 



