﻿248 FOSSIL MOLLTJSCA, ETC. FEOM NYASALAND. [May I9IO, 



E. A. Smith. ' On a Collection of Shells from Lakes Tanganyika & ISTyassa & other 



Localities in East Africa ' Proc. Zool. Soc. Lond. 1881, p. 283 & pi. xxxiii, 



fig. 11. [AcJiatina craveni.~] 

 E. A. Smith. ' On a Collection of Land-Shells from British Central Africa ' Proc. 



Zool. Soc. Lond. 1899, pp. 579-92 & pis. xxxiii-xxxv. [Pomabias nyasanus.~\ 

 R. Tate. ' On some Secondary Fossils from South Africa ' Quart. Journ. Geol. Soc. 



vol. xxiii (1867) p. 143. [Karroo shells from Kat River and Graaf Reinet 



are referred to, and regarded as of Triassic age.] 



EXPLANATION OF PLATE XVIII & PLATE XIX (pars). 



Plate XVIII. 



[The figures on this plate are of the natural size, with the exception of 

 fig. 5, which represents a magnification.] 



Quaternary Gastropoda. 



Viviparus unicolor (Olivier). 



Fig. 1. An example of the limestone from Chisali, composed entirely of the 

 casts of this gastropod. Natural size. 



2. "Wax reproduction of specimen made from the largest cavity repre- 



sented on surface of fig. 1. 



3. Front view of an isolated form from Chiwondo. Natural size. 



4. Dorsal aspect of same specimen. 



5. Surface of same, showing striated sculpture, magnified. 



Lanistes solidus, E. A. Smith. 



Fig. 6. Front aspect of a medium-sized example from Chiwondo. Natural size. 

 7. Dorsal view of the same specimen. 



TiioriDorHORA nyasaka, E. A. Smith. 



Fig. 8. Example of an adult form from Chiwondo, exhibiting a front view. 

 Natural size. 

 9. Dorsal aspect of the same shell. 



Plate XIX (pars). 



[Figs. 13-18 have been drawn with the aid of the camera lucida, 

 and are magnifications.] 



Permo-Carboniferous Pelecypoda. 



Pal/eomutela oblonga (T. R. Jones). 



Fig. 11. External view of two right valves of different sizes attached to the 

 matrix. Natural size. 



12. Similar view of another right valve, showing the periodical growth- 



lines and fine intermittent striations. X 2. 



13. Section of the posterior portion of the hinge-area of a fragmentary 



right valve, showing a succession of shell-growths forming narrow, 

 elongate, >-shaped teeth. X 8. 



14. Dorsal aspect of the specimen represented by fig. 12, exhibiting the seg- 



mented mineralized remains of the ligament reposing in the elongate 

 posterior depression. X 8. 



Permo-Carboniferous Crustacea (Phyllopoda). 



Estheriella nyasana, sp. nov. 

 Fig. 15. External view of a pair of extended valves showing oblong form. X 8. 



16. Enlargement of the same specimen, exhibiting growth-lines and obscure 



radial striations. X 30. 



17. An example of a right valve of subquadrate contour. X 8. 



18. Profile of a specimen with closed valves, showing moderate and 



regular convexity. X 8. 



