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Show 1893.] SHELLS FROM BRITISH CENTRAL AFRICA. 639 23. MELANIA MWERUENSIS. (Plate LIX. fig. 12.) Testa elongata, acuminata, albida, punctis rufis, in seriebus transversis dispositis, ornata, epidermide tenuissima pallide olivacea induta; spira elongata, acuminata; anfractus circiter 10, fere plani, inferne ad suturam leviter constricti vel canaliculali, plicis obliquis sulcis spiralibus decussatis instructi, infra suturam crasse marginati vel bdlteati, ultimus plicis prope medium obsoletis, inferne transversim sulcatus ; sutura parum obliqua ; apertura acuminato-ovalis, superne angustata, longit. totius ^ paulo superans; labrum tenue, superne late et subprofunde sinuatum; columella curvata, alba, incrassata. Longit. 22 millim., diam. 8; apertura 7 longa, 4 | lata. Hab. Lake M w e r u (R. Crawshay). This species, although spotted like M. tuberculata, is sufficiently distinct from that form. The plica? are coarser, the whorls flatter, and the lip more sinuated. The spiral sulci are four in number on the upper whorls and about eight on the body-whorl; they cut through the oblique folds, giving them a more or less nodose appearance. The red dots, which are sometimes produced into short transverse lines, fall upon the ridges between the sulci, and never in the grooves themselves. In some specimens the oblique costae are almost obsolete, especially upon the last and penultimate whorl. 24. MELANIA IMITATRIX. (Plate LIX. fig. 13.) Testa elongata, acuminata, epidermide luteo-olivacea amicta, punctis rufis paucis sparsis picta ; anfractus 8-9, fere planiusculi, costis oblique arcuatis 16-18, quadriscriatim cjranosis, instructi, ultimus infra medium transversim sulcatus; apertura ovata, superne acuminata, longit. totius 5 aclcequans; labrum supra late sinuatum, antice prominens; columella inferne arcuata, incrassata, alba, reflexa. Longit. 21 millim., diam. 8; apertura 7 longa. Hab. Lake M w e r u (R. Crawshay). This species is like M. tuberculata, but has less coarse whorls, more distinct ribbing and granulation. 25. MELANIA CRAWSHAYI. (Plate LIX. fig. 14.) Testa angusta, elongata, albida, epidermide pallide olivacea induta ; anfractus 9, infra suturam serie conspicua, obliqua, conferta tuberculorum cincti, infra nodulos constricti, deinde convexiusculi, lirisque tribus, quarum snprema nodosa, spiraliter instructi, ultimus liris circiter 9 cinctus; apertura anguste ovata; labrum tenue ; columella arcuata, alba, incrassata. Longit. 17 millim., diem. 5|; apertura 5 | longa, 3 | lata. Hab. Lake M w e r u (R. Crawshay). The row of tubercles bordering the suture is prominent and very remarkable. Beneath comes a broad constriction, below which are three transverse ridges, of which the uppermost is ornamented |
