. Bulletin of the British Museum (Natural History). TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 227 Remarks. Oligoccnc specimens vary somewhat from the holotype and are distinguished as Morphotypcs A and B, below. H. dameriacensis Keij 1958 has a similar shape to H. mongoensis but differs in its less angular posterodorsal loop, its smooth rounded subccntral tubercle, and in the way the posterodorsal ridge joins the dorsal and ventral ridges; this junction is defined better than in H. mongoensis. Morphotype A PI. 22, figs 3-7 Figured specimens. Two female valves, OS 8238-9, and a
. Bulletin of the British Museum (Natural History). TERTIARY OSTRACODA FROM THE LINDI AREA, TANZANIA 227 Remarks. Oligoccnc specimens vary somewhat from the holotype and are distinguished as Morphotypcs A and B, below. H. dameriacensis Keij 1958 has a similar shape to H. mongoensis but differs in its less angular posterodorsal loop, its smooth rounded subccntral tubercle, and in the way the posterodorsal ridge joins the dorsal and ventral ridges; this junction is defined better than in H. mongoensis. Morphotype A PI. 22, figs 3-7 Figured specimens. Two female valves, OS 8238-9, and a male left valve, OS 8240. Sample FORM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. Other material. Seven specimens. Dimensions (^m). Female right valve OS 8238 Female left valve OS 8239 Male left valve OS 8240 L H W 810 450 270 745 445 245 840 455 280 Remarks. Morphotype A differs from typical H. mongoensis in details of ornamentation; the posterodorsal loop is less sharp and the parts of the median ridge are differently arranged. Morphotype A clearly represents an earlier stage in the evolutionary development of Hermanites mongoensis, s. str. Morphotype B PI. 22, figs 8-10 Figured specimen. A male left valve, OS 8242. Sample FCRM 1578, coastal cliff west of Ras Tapuri; Middle Oligocene. The only specimen. Dimensions {\im). Male left valve OS 8242 L 710 H 370 W 235 Remarks. Morphotype B is rectangular. In lateral view the ventral margin is strongly modified by the overhanging ventral ridge, which gives it a distinctive shape. HermanitespercuHus sp. nov. PI. 21, figs 7-12; Fig. 8 Name. 'Highly ornamented', with reference to the strongly reticulated surface. Diagnosis. A species of Hermanites with a strongly reticulate lateral surface, a straight, pronounced ventral ridge and a raised posterodorsal tubercle, which gives it a characteristic appearance in dorsal view. Holotype. A female carapace, OS 8226. Five carapaces, OS 8227-31, are paratypes. Sample FCRM 2033, Li
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