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Vol. 70.] MOLLUSCAN REMAI~'S FROSt TIIE VICTORIA NYAmZA. 187 APPE~'I)Ix III. On-some.NoN-~'LtRI~'E MOI,LUSCAX RE.~IAI.~'S f,'Om the VICTORI& ~N~YA~XZA ]{EGION, ASSOCIATED with MIOCENE VERTEBRATES.1 ~BV RIclI.tl~D BULLEX NEWTON, F.G.S. ~PLATE XXX.] Introduction. The material on which this eomlnunication is based wa~ obt;tined by Dr. ]~elix Oswald from a series of fluvio-lacustrine deposits occurring at ]qira, Kachuku, and Kikongo, which are situated cast of Karungu Bay, and therefore near the north- eastern corner of the u Nyanza, the furthest-removed locality from the lake-margin being Kikongo, which is distant some 5 or miles. From geological observatiofis made at these places, Dr. Oswald was able to construct a vel%ical section showing that the rock-suc- cession was divisible into thirty-seven beds of variable thicknesses, which, when added together, amounted to a total thickness of about 160 feet. Speaking generally, the mollusea were found through- out the deposits, and often in association with a snmll species of DinotJ~erium, and Chelonian, Croeodilian, and other vertebrate remains. The most valuable of these fossils was the Dinotherium, beeause it unmistakably indicated that the deposits containing it might be referred to the Burdigal!an stage of the Miocene Period. S~-atign*aphically, then, this was an important result; but it had been arrived at previously to the ' Oswald' expedition by Dr. C.W. %ndrews, F.R.S., ~ who reported on similar Dinotheriun, remains tom the same area, which had been collected by the late Mr. D. B. P~gott, and were afterwards presented to the British Museum by ~r. C.W. Hobley, C.M:.G., one of the Commissioners for ]}ritishEast Afriea. From a fragmentary mandible with teeth in sit,~, Dr. Andrews was enabled to recognize a new species of this genus, figuring and describing it as 1). hobleyi, as well as pointing out its affinities and ranking it as 'closely similar to D. cu~ieri' of Kaup, a characteristic mammal of the Bm'digalian beds of France. It is fortunate, therefore, that the vel~ebmte evidence enables us to determine so accurately the horizon of the deposits, because the molluscan remains would have utterly failed in this direction, from the fae$ that they represent existing species. The collection consists entirely of g'astropod gener~ of fluviatile and terrestrial character belonging to Amjoullaric~, Zanistes, Cleopatra, T,'opidophora, Achatina, Burtoa, Cerastus, and Zimicolaria--the total aosence r Peleeypoda being incidentally mentioned as remarkable, since 1 Communicated by permission of the Trustees of the British !~Iuseum. .o , On a New Species of Dinotherimr~ (D. hob~eyi) from British East Africa' Proc. Zool. Soc. London, 1911, p. 943 & pl. xlviii. 188 ~1~. R. B. ~'EWTON O~" ~'OX-MARI5-E MOLLUSCAN [June ~9 ~4, the group is so well represented in the waters of the Victoria Nyanza at the present day. The more abundant shells are the freshwater genera Ampullarict, Lanistes, and Cleopatra; whereas the remaining or terrestrial forms are few, and appear to be extremely rare. So far as past distribution is concenaed, only three of the species have been pre- viously recorded from geolo~eal deposits: namely, Ampullaria ovata and Zauistes carinatus, both of which occur in the late post- Pliocene beds of Egypt (Fayfim) ; and also ~'opidoThora nyasana, which has been found in beds of similar age on the Lake Nyasa plateau. Among the freshwater forms, only the ,~mpullaria is known as living in the Victoria Nyanza, while the nearest water for Zanistes carinatus appears to be the Tana River, a consider- able distance east of that lake. Lake Rudolf and the Mombasa- Zanzibar waters are the nearest available regions for obtaining- ~leoflatra buh:moides, while C. exa~'atct is found only in the last- named district. The land-shells are mostly restricted to the Nile and lake countries of Eastern Africa. In the following table the dista'ibution is set out more fully :- TABLE SHOWII~O THE DISTRIBUTION OF THE SHELLS COLLECTED BY DR. OSWALD. :, : ]Recent. , ~i=~ ~ ",~= .,!~: I ~,~ Genera and Species. I'. t~l:., .,"~_1 .,,.-. ~.~ i~:_i~___l~___!~_Z_l = -et~. __ N ~ Freshwater. ,4m2aullaria ovata ......... X X ... X X iI• "'" X ]Lanistes earinat~es ...... )< X ... )< Cleopatra bulimoides ...... X Cleoyaatra exarata ...... X .. ~ ......... Terrostrial. 1 Tropidophora nga#ana .... X ,.. ~ .., Aehatina sp................ I ,,( Burtoa el. nilotiea ......... i :K ...IX Cerastus cf. moellendord~ ' X ....... • • Cerastus sp ................ i X : i Limicolaria sp............. "l 1 i i In no other region of Africa has a similar molluscan fauna of this age been found, the only Burdi~lian beds known being those of Mogham 1 and Wadi Faregh ~ in Egypt. They are, however, differently constituted, having involved marine as ~Tvellas estuarine conditions in their formation, as proved by their fossil contents, which consist of marine mollusca, eehinoids, polyzoa, etc., as 1 C. W. Andrews, Geol. lV~ag,dec. 4, vol. vi (1899) pp. 481,482. : E. S~romer, Abhand/. Senckenb. Natttrf. Gesellsch. vol. xxix (1907) p. ~3. VOt. 70.] RESfAI.NS :FROM THE YICTO:RIA I~YANZi 1REGIO~N'. 189 well as land-animals (Bodoc~e,~is, Brachyodus, etc.), and plants (palms). Ccl~ain sandstone-beds in the Moghara region are inter- calated with marine and terrestrial deposits, and are full of the small _Palu(leslrina (=Z-[]/drobia): hence Dr. M. ]31anckenhorn I has regarded them as equivalent in age to the 'Hydrobien-Schichten ' of Europe, which is part of the Burdigalian stage of the Miocene. It would seem, therefore, according to Dr. Oswald's z preliminary account, that the deposits in question represent the delta of an old river which, during Lower Miocene or Burdigalian times, ran into the Victoria Nyanza at Karungu. The present molluscan evidehee would indicate that the genera Za~tistes and Cleopatrcl formed part of the lake-fauna at that period, although they have since become extinct in those waters, only the AJnlndla~'ia surviving to the present day. Among the terrestrial shells, Burtoa, is the sole genus found in the neighbourhood of the lake, whereas the others occur in locaEties at considerable distances therefrom. Finally, it may be stated that the molluscan renmins consist largely of natural casts in clays, marls, and sandstones of different shades of colour, the .prevailing tint being grey; there are, besides, occasional specimens which are better preserved, and in which the details of shell-structure can be seen. I desire to thank my friend Mr. Edgar A. Smith, I.S.O., of the British Museum, for advice and assistance during the preparation of these notes. Description of the Specimens. Freshwater Forms. Family A_~u,tT~mxi~rn)~. A~[PVLn.tRLt OVXWi Olivier. (P1. XXX, figs. 14.) Arnp~dlaria ovata Olivier, 'Voy. Emp. Othomau, ]~gypte, Perse' 180~ (An 12) vol. ill, pl. xxxi, fig. 1 & p. 67 : E. yon Martens, ' Beschalte Weichthiere Ost- Afrikas--Deutsch-Ost-Afrika' (K. MSbius) vol. iv (1898) p. 158 ; E. A. Smith, Prec. Malac. Soc. London, vol. vi (1904) p. 100. :Pachglabra ovata Kobelt, Kuster's ~Conchyl.-Cabinet ' pt. 556 (1912) p. 46. Original diagnosis :--Oblongo.ovata, subcarnea, i~tus alba ; umbilieo angusto, recurve ; marffi~te columellari obtecto. R e m a r k s.--The specimens referred to this species consist mostly of matrix-casts of various sizes, with more or less imperfect and fractm'ed margins. In adult forms the spil~l region would appear to be rather more produced than in smaller specimens--although the relative proportions are similar, and entirely agree with what obtains among living shells brought home by Dr. Oswald from the waters of the Victoria Nyanza. A few of the smaller or inter- mediate examples have some shell-structure preserved, in which the longitudinal sta%tions can be traced; but there is no evi- dence of the spiral bands. * Zeitschr. Deutseh. Geol. Gesellsch. vol. liii (1901) p. 102. 'Daily Telegraph' April 5th, 1912, ~nd Geogr. Journ. vol. xli (1913) p. 114. 190 .~R. 1~. B. 5-EWTON OS NON-)I&RINE MOLLUSC&h" [June 1914, OccmTing with these specimens are a number of isolated opercula of large, thick, and robust clml~cter, and, nmreover, of calcareous stl~cture. Only one fmgmentalT example is obselwed to be more or less in situ, covel~ing the broken aperture of one of the smaller forms of this species. Dimensions in millimetres:-- Shellf Height varying from 18 to 45. Diameter (maximum) varying from 15 to 45. O , f Height = 33. percu~um ~[ Width=20. Distribution.'-Although there are no rccoMs of the existence of this species in the waters of Birket el Qm~n, it occurs in the late post-Pliocene deposits of that district of Egypt (exalnples are pre- served in the British Museum and in the Cairo Musetun). Besides the original locality of Lake Mareotis, this mollusc has been found in the region of the White Nile, the Victoria Nyanza, Lakes Tan- ganyika and Nya~, as well as in parts of Portuguese West Africa. Occurrenee.--The specimens were mostly discovered in Beds 1~ & 15, associated with re~mins of Chelonia, Crocodilia, and Lanistes carinatus. More isolated examples are represented from the following beds :- Bed 16. Opercula only--associated with Hymcoid, Crocodilian, and Chelonian remains and Gleopatra. Bed 17. ~ Accompanying Chelonia and Crocodilia. Bed 19. J * Bed 21. With Lanistes carinatus, and vertebrates similar to those found in Bed 17. Bed 2"~. Opercula only--with 3)inotherium and other velffe- bl,-ltes. Bed 31. With Dinotherium and other vertebrates. Bed 32. With I, a uistes carinatus and Cteopatra. Bed 34. An isolated cast in brown marlstone. Localities.--Nira (Beds ]r 15,19, 24, 31, 32, 34) ; Kachuku (Beds 14~, 15, 16, 17, 21, 2'~); Kikongo (Bed 14).

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