92 HELIX-HELENOCONCHA. 



Patula (Endodontd) vernoni SMITH, P. Z. S. 1892, p. 262, t. 21, 

 f. 6-66. 



This species is at once recognized by its very flat spire, the com- 

 pressed very acute keel, the minute umbilicus, the single fine liration 

 upon the upper part of the body-whorl, running wichiii the aperture, 

 and the style of coloring. The red rays upon both the upper and 

 lower surfaces are more or less wavy and interrupted. There is no 

 other sculpture excepting the fine lines of growth which cross the 

 upper surface of the whorls obliquely and are a little flexuous 

 beneath. The body-whorl has a more distinct impression below the 

 keel than above it. I have much pleasure in naming this very dis- 

 tinct species after my late friend, T. Vernon Wollaston, whose work 

 Testacea Atlantica is one of the most accurate and complete hitherto 

 published upon any Molluscan fauna. (Smith.') 



P. BIPLICATA Sowerby. Unfyured. 



Shell orbiculate-depressed ; whorls 5, rounded, striated. Aperture 

 semilunar ; parietal wall having two spiral folds, the upper one 

 larger. Umbilicus large. Alt. 1, diam. 2 mill. (Soivb.*) 



Northern part of St. Helena. 



Helix biplicata SOWB. in appendix to Darwin's Geol. Obs. on the 

 Volcanic Is. visited during the Voy. H. M. S. ' Beagle,' p. 158 

 (1844). Patula biplicata WOLLASTON, Test. Atlant., p. 538. 



This species has been found only in a subfossil condition. It 

 differs from H. bilamellata in the larger umbilicus, more exserted 

 spire, and the rounded, not carinated whorls. 



P. PSEUSTES Smith. PI. 36, figs. 16, 17, 18. 



Shell conoid, pyramidal, narrowly umbilicated ; whitish, painted 

 above with square spots, below with flames of reddish ; whorls 6, 

 convex, separated by a deep suture, radially delicately costulate, the 

 last whorl rounded at the periphery, sculptured beneath with very 

 delicate flexuous stria? ; aperture lunate, oblique, having six unequal 

 denticles within (2 lamelliform, on parietal wall, 3 smaller on the 

 columella, and 1 in the middle of the palate) ; peristome thin, mar- 

 gins remote, the columella slightly dilated. 



Alt. 21, diam. 3 mill. (Smith.') 



Flagstaff Hill, St. Helena (extinct.) 



Patula (Endodonta) pseustes SM., P. Z. S. 1892, p. 262, t. 21, f. 

 7-76. 



