OCR Text |
Show 1893.] SHELLS F R O M BRITISH C E N T R A L AFRICA. 637 A subsequent examination of the animal has apparently proved that^ there is not sufficient reason for separating it. The present species is remarkable for its conical spire, the conspicuous keel around the middle of the body-whorl, and its somewhat wide umbilicus. In shells belonging to the variety, the whorls are almost flat and without the shouldering at the upper part observable in typical examples, and the peripheral keel winds up the spire above the suture, producing a decided pagoda-like appearance. The operculum is thin, concentrically striated as usual, and also exhibits (especially upon the inner glossy surface) some more or less distinct radiating striae. 15. VIVIPARUS CRAWSHAYI. (Plate LIX. fig. 8.) Testa ovata, conica, rimata, carinata, cornea, epidermide tenui, olivacea, spiraliter et oblique striata, induta, versus apicem purpurea; anfractus 6, convexiusculi, ultimus ad peripheriam forte carinatus; apertura angulatim rotundata, longit. totius haud cequans; peristoma tenue, margine columellari arcuato, anguste reflexo, cdbo-cceruleo. Operculum normale. Longit. 18| millim., diam. 13; apertura 9 longa. Hab. Lake Mweru (R. Crawshay). This species resembles V. unicolor, Olivier, V. robertsoni, Frauen-feld, and a few others, but may be distinguished by its much more pronounced keel and conspicuous spiral striae. 16. VIVIPARUS CAPILLACEUS, Frauenfeld. Hab. Angoni-Land, south end of Lake Nyasa ( A Whyte). 17. CLEOPATRA JOHNSTONI. (Plate LIX. fig. 9.) Testa ovato-conica, vix rimata, epidermide olivacea induta, carinata spira conica, ad apicem erosa; anfractus 7, plani, inferne ad suturam carinati, lineis incrementi curvatis tenuibus sculpti, ultimus in medio carinatus, infra carinam convexiusculus, inter dum carina secunda minus conspicua prope medium cinctus ; apertura ovcda, superne et infra leviter acuminata, longit. totius ^ fere cequans, sordide vel cceruleo-albida ; peristoma continuum, margine externo tenui, superne haud profunde sinuato, columellari arcuato leviter incrassato et reflexo. Operculum primo paucispirale, exinde concentricum. Longit. \7 millim., diam. 10; apertura 8 longa, 6 lata. Hab. Lake Mweru (R. Crawshay). This is a very interesting species and recalls the general aspect of some of the North-American Pleuroceridce. Two of the three specimens at hand have the second feebler keel upon the body-whorl, and it is situated just below the peripheral carination. The operculum agrees precisely with that of G. bulimoides from the Nile. Named in honour of H . H . Johnston, Esq., O B . 18. CLEOPATRA MWERUENSIS. (Plate LIX. fig. 10.) Testa ovato-acuminata, anguste perforata, subtenuis, sordide |