OCR Text |
Show 1881.] SHELLS FROM SOCOTRA. 255 OTOPOMA CLATHRATULUM, var. MINOR. Shell closely umbilicated, very globosely turbinate, solid, polished, sculpture regular spiral ribbing, crossed by fine transverse irregular costulation; colour white, one specimen dark grey on the apex ; spire conoid, apex blunt, and smooth for 1| whorl; whorls 4\ ; aperture ovate ; peristome simple, strong, and attached close to the penultimate whorl. Operculum situated close to the peristome, very thick and shelly, the subcentral nucleus slightly sunken below the outer whorl; dark grey in central portion. Size:- Major diam. 0*54, minor diam. 0'40, alt. axis 0-40 inch. „ ,, 18*0 „ „ 15*3, „ „ 16*6 millims. ["On plain near Gollonsir village, very common." (I. B. B.) The greater number, however, are marked " very common, from the plain in vicinity of Kadhab."] This shell is very similar to the last, but only about half the size; and the difference in the position of the peristome with respect to the penultimale whorl is very marked and constant. OTOPOMA CONICUM, n. sp. (Plate XXVIII. fig. 1.) Shell conoid, closely umbilicated, solid; sculpture fine, regularly disposed spiral ribbing crossed by fine costulation, continued to well within the umbilical region ; colour white ; spire conic, sides rather flat, apex subacute; suture rather shallow ; whorls 5, the last well rounded, slightly descending, aperture circular, suboblique; peristome very thin; columellar margin simple, not reflected. Operculum shelly, solid, paucispiral, of 3 whorls, smooth subcentral nucleus depressed, concave behind. Size:- Major diam. 0*24, minor diam. 0"20, alt. axis 0-32 inch. » « 11'0, „ „ 10*0, „ „ 7'0 millims. [" From the plain about Gollonsir village." (I. B. B.)] OTOPOMA TURBINATUM, n. sp. (Plate XXVIII. fig. 2.) Shell turbinate, umbilicated; sculpture regular, fine, equally distributed, spiral ribbing smooth on the last whorl near umbilicus; apex smooth ; colour white ; spire pyramidal, suture impressed ; whorls 41, well rounded ; aperture nearly circular, slightly angular above ; peristome thin, much curved on the columellar margin. Operculum not obtained. Size:- Major diam. 8-8, minor diam-, 7'9, alt. axis 5-0 millims. „ „ 0-35, „ „ 033, „ „ 0-23 inch. [." O n stems of Draca?na cinnabari, Balf. fil., at 2000 feet elevation, on limestone." (I. B. B.).] Only three specimens were obtained. TROPIDOPHORA SOCOTRANA, n. sp. (Plate XXVIII. fig. 3.) Shell trochiform, umbilicated, rather solid; sculpture three stron» |