HELIX-ACAVUS. 79 



Meth., t. 462, f. 4. H. acava VALENCIENNES in Paris Mus. 

 Acavm hcemastomus MONTF, Conch. Syst., p. 235, t. 59. SEMPER, 

 Reisen im Arch. Phil., Land Mollusken ii, p. 99, t. 12, f. 8-10 

 (Anatomy). 



This species is smaller and less globose than H. phoenix, and has 

 clearly denned dark encircling zones. There is great variation in 

 banding, as the figures on plate 18 show ; and very rarely bandless 

 specimens occur (fig. 23). 



It may be noted that the columella is entirely red in the typical 

 form having no white spot at its insertion such as occurs in all other 

 species. 



The synonymy given above includes only references which may 

 be of use to modern students. PfeifFer cites many additional authors 

 in the Monographia. 



Benson collected this shell at Point de Galle, Ceylon. He says : 

 The trunks of the mangoe trees were literally encrusted with living 

 specimens of hcemastoma, with its gorgeous red peristome and chest- 

 nut and milk-white bands, the splendor of which was invariably 

 concealed by a coating of green fsecula, which served in some mea- 

 sure to screen the shells, which otherwise by the contrast of colors 

 would have been too conspicuous to their enemies. On a single tree 

 I counted thirty specimens within reach. 



Var. MELANOTRAGUS Born. PL 18, fig. 24. 



Peristome and a broad band across the parietal Avail black ; a 

 white spot at the insertion of the columella. 



This variety is nearly as abundant as the typical red-lipped form. 



Var. CONUS Pilsbry. PI. 16, fig. 7. 



More elevated and conical than the type, with which it agrees in 

 the color of the outside. The entire peristome, colnmella and a 

 broad band across the parietal wall are a beautiful lilac or purple 

 color ; a rather deep excavation at the place of the umbilicus. 



Alt. 36, diarn. 35 mill. 



H. FASTOSA Albers. PL 16, figs. 5, 6. 



Shell imperforate, globose-conical, regularly, closely striate, whit- 

 ish, obliquely streaked, and multifasciate with tawny ; spire conic, 

 rather obtuse; whorls 4, a little convex, rapidly increasing, the 

 last descending in front ; periphery most obsoletely subangulated ; 

 aperture diagonal, obliquely oblong, white inside ; peristome liver- 



