254 LIEUT.-COL. H. H. GODWIN-AUSTEN ON [Feb. 1, 



inferior figure represents a shell with a high spire, not nearly glo- 

 bular : it is certainly not to be identified with Sowerby's figure in 

 the Thes. Conch, pi. xxvi. 



Otopoma complanatum, n. sp. (Plate XXVII. figs. 3, 3 a.) 



Shell turbinate, openly umbilicated, fine spiral ribbing crossed 

 by transverse finer ribbing, smooth on base ; colour white ; spire 

 pyramidal, 1| whorl at the apex smooth; suture impressed; 

 whorls 5, sides well rounded ; aperture ovate, suboblique, angular 

 above ; peristome continuous, thickened and scarcely reflected on 

 the outer margin, which is well rounded ; columellar margin oblique 

 to axis, thin, with a well-marked submedian angulation near the 

 umbihcus, but with no tendency to an expansion in that direction. 



Size : — 



Major diam. 36*8, minor diam. 29*5, alt. axis 16*8 millims. 



[" Very common on the limestone plains from more than one 

 locality, and common on the land towards the east end of the island ; 

 all the land in this region is elevated over 700 feet and is of lime- 

 stone." (I. B. B.)] 



Somewhat like Cyclostoma albicmis, Sow. Thes. Conch, p. 118, 

 pi. xxvi. figs. 1 10-112, in form of the aperture and its smooth surface. 



Otopoma clathratulum, var. socotrana. (Plate XXVII. 



figs. 4, 4 a.) 



Shell very globosely turbinate, closely umbilicated, spiral ribbing 

 on the apical whorls crossed by transverse striation, becoming 

 smoother on the body-whorl, which only shows the latter; colour 

 white, also pale purple, stronger on the apex ; bordering the suture 

 in one specimen numerous pale purple bands of colour occur, show- 

 ing darkish above the periphery (fig. 4 a) ; spire pyramidal, suture 

 impressed ; whorls 4, well rounded ; aperture subvertical, oval, 

 angulate above ; peristome continuous, almost separated from the 

 penultimate whorl, not reflected, thickened on the outer margin ; 

 columellar margin suboblique, nearly straight, with only a very 

 slight tendency to angulation. Operculum shelly, situated close to the 

 peristome, paucispiral, of three whorls rapidly increasing, nucleus 

 .subcentral, flat in front. 



Size : — 



Major diam. 28'5, minor diam. 22'6, alt. axis 13*5 millims. 

 1-22, „ „ 0-88, „ 0-55 inch. 



[" Very common everywhere." (I. B. B.)]. 



This species is very closely allied to 0. clathratulum, Recluz, figured 

 in Conch, Icon. pi. xviii. fig. 116b ; but in none of the Socotran shells 

 do we find the columellar margin expanded, as seen in Mr. Sowerby's 

 drawing ; and I have examined the specimens in the British Museum : 

 fig. 116 a is that of a well banded specimen, but is much over- 

 coloured. Both Arabia and Socotra are given as the habitat of this 

 species ; but there is some doubt as to which locality the above speci- 

 mens are to be assigned to, as they are stuck upon the same tablet. 



