Yd. 70.] EEMAIXS FEO^I THE YICTOEIA NTAWZA EEGIOX. 189 



well as land-animals (Podocnemis, JBrachyodus, etc.), and plants 

 (palms). Certain sandstone-beds in the Moghara region are inter- 

 calated with marine and terrestrial deposits, and are full of the small 

 Paludestrina ( = Hydrobia) : hence Dr. M. Blanckenhorn l 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 3 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 evidence 

 would indicate that the genera Lanistes and Cleopatra formed 

 part of the lake-fauna at that period, although they have since 

 become extinct in those waters, only the Ampul! aria surviving to 

 the present day. Among the terrestrial shells, JBurtoa is the sole 

 genus found in the neighbourhood of the lake, whereas the others 

 occur in localities at considerable distances therefrom. Finally, it 

 may be" stated that the molluscan remains 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. 

 Eamilv Ampullaeiidj:. 

 Amplllaeia ovata Olivier. (PI. XXX, figs. 1-4.) 



Ampullaria ovata Olivier, ' Voy. Erap. thorn an, Egypte, Perse ' 1804 (An 12) 

 vol. iii, pi. xxxi, fig. 1 & p. 67 : E. von Martens, ' Beschalte Weichthiere Ost- 

 Afrikas— Deutsch-Ost-Afrika' (K. Mobius) vol. iv (1898) p. 158 ; E. A. Smith, 

 Proc. Malac. Soc. London, vol. vi (1904) p. 100. 



Pachglabra ovata Kobelt, Knster's 'Conclvvl. -Cabinet ' pt. 556 (1912) p. 46. 



Original diagnosis : — Oblongo-ovata, subcarnea, intus alba ; umbilico angusto, 

 recurvo ; margine coluviellari obtecto. 



Remarks. — The specimens referred to this species consist mostly 

 of matrix-casts of various sizes, with more or less imperfect and 

 fractured margins. In adult forms the spiral 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 Xyanza. A few of the smaller or inter- 

 mediate examples have some shell- structure preserved, in which 

 the longitudinal striations can be traced ; but there is no evi- 

 dence of the spiral bands. 



1 Zeitschr. Dentsch. Geol. Gesellsch. vol. liii (1901) p. 102. 



2 'Daily Telegraph' April 5th, 1912, and Geogr. Joum. vol. xli (1913) 

 p. 114. 



