544 TESTA Ci: A ATI ANTIC A. 



Bulirnus digitalis, Reeve, Conch. Icon. f. 308 



„ relegatus? Bens., Ann. Nat. Hist. vii. 204 (1851) 

 „ helena, Melliss, St. If el. 122 (1875) 



Habitat versus borealem insula), semifossdis ; in excelsis 

 prseruptis, super terram jacens, fere quasi in statu recenti, hinc 

 inde vulgaris. 



The present Bulirnus, which was admirably figured by Quoy 

 in 1833, occurs rather abundantly on the extreme summit of the 

 Barn, and in that immediate neighbourhood, lying loosely on 

 the surface soil, beneath the shrubs of Salsola, &c, — where it 

 has much the appearance of having lived at a comparatively 

 recent period. At all events many of the examples have their 

 colour and outer cuticle completely preserved, — though it is 

 equally true that the majority of them are decomposed, decor- 

 ticated, and colourless. It is far from unlikely therefore that 

 the species may still linger on in that particular district, though 

 I have no evidence that it has ever been met with in an abso- 

 lutely living condition. Yet so little altered are some of the 

 specimens, in their general features, that Pfeiffer makes no 

 allusion to the B. helena as being ' subfossilized 5 at all, and 

 Benson {Ann. Nat. Hist. vii. 263) does not hesitate to speak of 

 it, in 1851, — though, as I cannot but think, without sufficient 

 enquiry, — as ' recent.' Mr. Melliss remarks that, ' although the 

 shells are now dead, they appear of a more recent date than 

 those of the other species.' I possess a considerable number of 

 this Bulimus which were taken by Colonel Warren, and bv 

 Mr. P. Whitehead, on the Barn, as well as others by Mr. N. 

 Janisch in that immediate vicinity. 



The B. helena is ovate-conical in outline, thin in substance, 

 and (when in a sufficient state of preservation) of a yellowish- 

 brown hue ; its suture is very deeply and suddenly impressed, 

 causing the anterior edge of each whorl to appear (though not 

 exactly prominent) somewhat abruptly terminated (a fact which 

 gives an obtusely subangulate, or rather elbowed, shape to the 

 outer lip of its aperture at the point of insertion) ; its perfora- 

 tion is distinct and deep ; its peristome is acute, with the mar- 

 gins joined by an intervening lamina ; and its surface is densely 

 crowded with irregular costulate lines of growth, which are de- 

 cussated by more remote spiral ones, — more or less evident 

 according as the specimens are fresh, and free from superficial 

 decomposition. 



So far as I am able to form an opinion from a short diag- 

 nosis unaccompanied by a single observation, I should say that 

 the B. relegatus of Benson differs in no respect whatsoever from 

 Quoy's B. helena, — as represented by the bleached, colourless, 

 and strictly subfossilized aspect of that species. 



