OCR Text |
Show 254 LIEUT.-COL. H. H. GODWIN-AUSTEN ON [Feb. 1, inferior figure represents a shell with a high spire, not nearly globular : it is certainly not to be identified with Sowerby's figure in the Thes. Conch, pi. xxvi. O T O P O M A C O M P L A N A T U M , 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 umbilicus, 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 limestone." (i. B . B.yj Somewhat like Cyclostoma albicans, Sow. Thes. Conch, p. 118, pi. xxvi. figs. 110-112, in form of the aperture and its smooth surface. OTOPOMA CLATHRATULCM, var. SOCOTRANA. (Plate XXVII. figs. 4, 4a.) 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, showing 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 snbcentral, 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 O. clathratulum, Recluz, figured in Conch, Icon. pi. xviii. fig. 116b; but in none of the Socotran shells do we find the columeilar margin expanded, as seen in M r . 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 specimens are to be assigned to, as they are stuck upon the same tablet. |