HELIX-MACROON. 57 



Alt. 29, greater diam. 23 mill. ; aperture, oblique alt. 18, breadth 



15 mill. 



Madagascar. 



H. viridis DESH., in Lam., An. s. Vert., p. 102. PFR. Monogra- 

 phia i, p. 225 ; Conchy lien Cabinet, p. 297, t. 50, f. 9-12. REEVE, 

 Conch. Icon., f. 182. Bulimus viridis Dh., PER. Monogr. iii, p. 298. 

 Orthostylus viridis of Albers and Beck ; Orusta viridis Morch. 

 Cochlodryas viridis Dh., in Pfeiffer's Noment. Hel. Viv., p. 206. 



The principal variations are illustrated on my plate. The ground- 

 color is sometimes chestnut or olive-brown all over, unicolored or 

 with dark brown zones ; in these the lip is of a light flesh-color. 

 Some shells have the dark zones very wide, almost concealing the 

 green ground color. Figure 50 represents a shell of normal propor- 

 tions and coloration. The relationship of this species to H. cerina 

 was first pointed out in Novitates Conchologicse, vol. v. 



H. CERINA Morelet. PL 63, figs. 53, 54, 55. 



Shell covered-perforate, very narrowly perforate when immature, 

 globose, thin but solid, opaque, of a rich smoky chestnut color, shad- 

 ing into bright yellow at the umbilical region and on the next to the 

 last whorl, the inner whorls porcelaneous bluish-white, the apex deep 

 purple ; a narrow black baud margins the suture below, and a wider 

 one encircles the periphery. The surface is polished, glossy, under 

 a lens faint, fine incremental and spiral striae appear. The spire is 

 rather elevated, blunt ; apex not raised, the apical whorl dark 

 purple ; i&utures slightly impressed. Whorls 4-41, convex, the last 

 globose-depressed, convex above, below and at periphery, a trifle 

 deflexed in front. Aperture oblique, semilunar, opaque white and 

 showing the band inside ; peristome a little thickened and expanded, 

 dark, margins distant ; columellar margin straightened, narrowly 

 reflexed above. Alt. 18, greater diam. 23, lesser 18 mill. 



Madagascar. 



H. cerina MOREL. Journ. de Conchyl. 1877, p. 217. PER. in Nov- 

 it. Conch, v, p. 180, t. 153, f. 4-6. 



In its compact, subglobose form, glossy surface and beautiful 

 coloration, this species is very distinct. The contour is different 

 from the larger, elevated H. viridis, and the banding is peculiar. 



Subgenus XVIII. MACROON Pilsbry, 1890. 

 This subgenus is proposed for a number of sections which com- 

 prise most of the largest known Helices. The group as a whole is 



