82 HELIX-ACAVUS. 



shape, the upper and lower margins subparallel. The peristome is 

 very broadly expanded and revolute, its face white, shading toward 

 the outer edge into a beautiful reddish-chestnut color ; the back of 

 the reflected lip is white, or when not denuded of the very thin 

 epidermis it is yellowish. The broad columellar plate is generally 

 very distinctly truncated at the base ; it is white. The parietal 

 callus is usually bordered with chestnut-color. 



Alt. 40, diam. 49 mill. 



Ceylon. 



H. superba PFEIFFER, Zeitschrift fur Malak. 1850, p. 71 ; Mono- 

 graphia iii, p. 185 ; Kiister's Conchyl. Cab., p. 342, t. 133, f. 1, 2. 

 REEVE, Conch. Icon., f. 368a, b. 



A beautiful shell, separated from H. phoenix, hcemastoma, fastosa 

 and prosper a by its decidedly more angulated periphery. It is more 

 or less malleated or obliquely plicate on the back of the body- whorl. 

 The lip is white toward the inner side, shading into a lovely carnel- 

 ion hue on the outside edge, and the back of the recurved portion is 

 white. 



The following forms are distinguishable as varieties. 



Yar. ROSEOLABIATA Nevill. PI. 16, figs. 1, 2. 



This form is somewhat larger than the typical superba. The sur- 

 face is scarcely malleated, and not obliquely plicate. The peristome 

 is more broadly expanded than in superba ; the lip, columella and a 

 band across the parietal wall of a deep rose color. There is a white 

 spot at the insertion of the columella. The columellar plate is ab- 

 ruptly truncated at its base. 



Alt. 42, diam. 60 mill. 



Ceylon. 



H. superba in HANLEY & THEOBALD'S Conchologia Indica, t. 

 127, f. 4. H. superba var. roseolabiata NEVILL, Journ. Asiatic Soc. 

 Bengal, vol. 50, pt. ii, p. 134, 1881. 



In its pristine condition this magnificent shell does not have so 

 pink an outer surface as the figures on the plate show. It is of a 

 chestnut or pinkish-purple color, covered, like all Acavus, with a 

 dull greenish coating. 



Var. GREVILLEI Pfeiffer. PL 12, figs. 47, 48. 



A little more elevated than the average superba; dark chestnut- 

 brown, with pink spire ; the face of the peristome and a parietal 

 band is black, the columella having a white spot at its insertion. 



