HELIX-HELENOCONCHA. 93 



This species has the spire more elevated and conical than the 

 other species of Patula from the island. P. cutteri Pfr. may approach 

 it somewhat, but that species is said to have only two parietal 

 lamellae, and two basal denticles near the columella. The present 

 species has an additional basal denticle, and a prominent thin 

 palatal lamella, which falls as it were between the two on the inner 

 or parietal side of the aperture. (Smith.') 



P. CUTTERI Pfr. Unficjured. 



Shell perforate, conoid-depressed, thin, rather closely chordate- 

 costate, scarcely shining, chestnut colored, tessellated with buff 

 above, obsoletely imdulately streaked below ; spire shortly conoid, 

 vertex minute. Whorls 5, convex, the last not descending, the 

 base a little convex. Aperture slightly oblique, lunar, having two 

 acute entering parietal laminae, and two dentiform basal ones, at 

 the columella ; peristome simple, straight, margins remote, the colu- 

 mellar margin slightly dilated above. 



Alt. 2-5, diam. 4'75 mill. (P/r.) 



Diana's Peak, St. Helena (living). 



H. cutteri PFR., Mai. Bl. 1856, p. 206; Monogr. iv, p. 155. 

 Patula (E)idodonta') cutteri SMITH, P. Z. S. 1892, p. 263. 



A small species, unknown to me, apparently similar in general 

 features to the preceding, but with only four teeth within the aper- 

 ture, two parietal and two basal near the columella, more narrowly 

 umbilicated and probably more strongly sculptured. 



P. POLYODON Sowerby. PI. 36, figs. 19, 20, 21, 22. 



See MANUAL III, p. 62. Smith writes as follows : This is the 

 most widely umbilicated of all the species of Patula from St. Helena, 

 and this feature alone is sufficient to distinguish it from the rest. 

 The whorls also, in adult shells eight to nine in number, enlarge 

 very slowly. The striae are fine, regular, arcuately oblique above, 

 and slightly wavy on the last whorl. There are three parietal line 

 extending far within the aperture, of which the upper and lower are 

 nearly always double. The plicse within the outer lip are almost 

 invariably (in adult shells) seven in number, subequidistant, but 

 not of equal thickness, two or three towards the columella being 

 stouter than the rest, which are slender and extend some distance 

 within. Diam. maj. 51 mill., min. 5, alt. 2J. 

 Side Path, Sugarloaf Quarry, Sugarloaf Ridge, St. Helena (extinct.) 



