

HELIX. 187 



color ; spire depressed-conic, regular, apex obtuse, white, suture not 

 impressed, closely submarginate above ; whorls 4?, sub-rapidly 

 increasing, the upper slightly convex, smooth, the following plane, 

 plicate, the last large, abruptly descending, subdilated, slightly 

 convex, encircled by a scarcely undulating carina, more convex 

 below, subinflated, smoother; aperture very oblique, angulate-ovate ; 

 peristome subacute, slightly labiate within, the margins converging, 

 the basal deeply arcuate, briefly reflexed, columellar very short, 

 broadly expanded over the umbilicus. Diam. 33, alt. 19 mill. 



Ins. Gomera, Canaries. 



This fossil form has no near allies. It has been placed by various 

 authors in Leptaxis, Lampadia and Iberus. Mabille, however, 

 groups it with H. cuticula, a form bearing even more resemblance 

 to Lampadia. (= Mitra Albers.) 



Section VI. PLEBECULA Lowe, 1852. 



This section is confined to the Madeira Is. Its more prominent 

 -characters are the globose form and profound sutures. Helicomela 

 Lowe, 1854, is a synonym. 



H. PUNCTULATA Sowerby, 1824. PL 51, figs. 1-4, 98, 99. 



Nearly covered perforate, globose, rather thin, chestnut colored, 

 with a light corneous peripheral band, base corneous ; with rather 

 coarse incremental wrinkles, the whole surface covered with minute 

 setigerous granules, base smoother ; spire conic, slightly turreted ; 

 sutures impressed ; whorls 5, the apical nearly plane, rugose, convex, 

 the last inflated, rapidly widening, slightly descending anteriorly ; 

 aperture slightly oblique, narrow-lunar; peristome scarcely thick- 

 ened; columella white, dilated and partly appressed over the 

 umbilical chink. Diam. 15, alt. 13 mill. 



Madeira Group, Ins. Porto Saneto and Southern Deserta. 



The reddish brown color is sometimes suffused over the entire 

 surface of the shell. Specimens nearly white are also found. The 

 thinner more elevated form found on the little island of Southern 

 Deserta (or Bugio) has received the name of var. avellana Lowe. 



H. BOWDICHIANA Ferussac, 1819. PI. 50, fig. 97. 



Large, globose, covered subimperforate, solid, destitute of cuticle 

 and color ; the whole surface irregularly wrinkled, base smoother, 

 above finely granulate ; whorls 5, separated by profound sutures, 



