84 HELIX-ACAVUS. 



istome, the entire columella and a broad band across the parietal 

 wall are blackish-brown. Alt. 33, greater diam. 52, lesser 37 mill. 



Ceylon. 



H. waltoni KEEVE, Proc. Zool. Soc. Lond. 1842, p. 49 ; Conch. 

 Syst. ii, t. 166, f. 23 ; Conch. Icon., f. 372. PFR. Monographia i, p. 

 19 ; Kiister's Conchyl. Cab., p. 267, 1. 121 , f. 1-3. P. & F. SARASIN, 

 Ergebnisse naturwissensch. Forschungen auf Ceylon i, 2tes Heft, 

 1888. (Embryology.) 



A lovely shell, of peculiarly beautiful and effective coloration. 

 The angular patches of hydrophanous epidermis are characteristic, 

 but unfortunately my artist did not reproduce this feature in the 

 figures. 



H. SKINNERI Keeve. PI. 18, figs. 17, 18, 19. 



Shell depressed-globose, the spire very low, small, obtuse ; peris- 

 tome very greatly thickened, violet or lilac in color. 



The shell is much smaller than that of H. waltoni, of an inflated- 

 depressed form, the spire flat and obtuse, projecting but slightly 

 above the body-whorl. Whorls 3J, the earlier 2 forming the nu- 

 cleus or embryonic shell, the post-embryonic growth consisting of a 

 little less than one volution. This body-whorl is globose-depressed, 

 descending in front, inflated beneath. The color is dull chestnut- 

 brown, the thin epidermis worn off on the base, showing the pink- 

 ish-gray substance of the shell. The epidermis, where not worn, is 

 seen to be closely flecked with golden specks. The surface is luster- 

 less ; there are numerous little-raised encircling ridges or cords on 

 the body-whorl, and under a strong lens the surface is minutely 

 granulate ; the whorls of the spire are decussated by subobsolete 

 spiral lines crossing growth-striae. The aperture is very oblique, the 

 interior, the parietal wall, the columella and lip of a violet or lilac 

 color. The outer lip is slightly expanded, its face thickened by 

 a callous growth extending 5 millimeters or more in front of the 

 expansion. Alt. 21 greater diam. 36, lesser 26 mill. 



Ceylon. 



H. skinneri REEVE, Conch. Icon., f. 1387. PFR. Monographia 

 iv, p. 219. HANLEY & THEOBALD, Conch. Ind., t. Ill, f. 1 

 Acavus skinneri FFLD. in Zool-bot. Ges. Wien 1869, p. 876. 

 SEMPER, Reisen in Archip. Philippinen, Land Moll, ii, p. 100, t. 

 12, f. 7 ; t. 16, f. 5. (Anatomy.) 



