ON SLEEPING SICKNESS. 321 



Fig. 16. Transverse section tbrougli the spermatbeca, showing communication with 

 the gut. sp.amp., spevmathecal ampulla; etwuw.^., communication with 

 gut; d.v., dorsal vessel; sep.gl., septal glands; u.n.c, ventral nerve-cord. 



17. Drawing of the ventral cliteilar region, lip, lip overhanging the groove in 



which the male pore is situated. 



18. Diagrammatic drawing of segments 10 and 11 of a young mature Enchy- 



trteid, showing the sperm-sacs, d.v., dorsal vessel; sp.s., spei'm-sac ; 

 V.V., ventral vessel ; ros., rosette of cells in the sperm-sac. 



Plate XLTX. 



Fig. 19. Transverse section through two copulating Enchytrseids. ov., ovary ; 

 cl.ep., cliteilar epithelium ; .sp.d., sperm-duct ; p.h., penial bulb ; p., penis ; 

 op., male opening; sp.gl., spermathecal glands; sep.gl., septal glands; 

 amp., ampulla of spermatheca ; gl., glands in the ventral cliteilar region ; 

 m., muscles attached to these cliteilar glands and the body-wall ; d.v., 

 dorsal vessel. 



20. Transverse section through segment 12 to show gland-like bodies in the 



ventral cliteilar region, d.v., dorsal vessel; ow., ovarj' ; cl.ep., cliteilar 

 epithelium; g., gland-like bodies continuous with the epidermis; ep., 

 epidermis ; v.n.c. ventral nerve-cord ; m., muscles connecting gland-like 

 bodies obliquely with the body-wall ; v.v., ventral vessel; c. in g., ciliates 

 in gut. 



21. Highly magnified section through the male opening, sp.d., sperm-duct; p., 



penis-like thickening ; op., male opening ; ^. ft., penial bulb; m., muscles 

 around the penial bulb ; g., ventral cliteilar gland. 



25. The Relationship of the Big Game of Africa to the spread 

 of Sleeping Sickness. By Dr. W. YoRKE, Liverpool 

 School of Tropical Medicine*. With an Appendix con- 

 taining Remarks by Sir John Bland-Sutton, F.R.C.S., 

 F.Z.S. ; Guy A. K. Marshall, F.Z.S. ; Prof. E. A. 

 MiNCHiN, M.A., F.R.S., V.P.Z.S. ; The Hon. L. Walter 

 Rothschild, D.Sc, F.R.S., F.Z.S.; Sir Henry Seton- 

 Karr, K.C.M.G., F.Z.S. ; and Sir Alfred Sharpe, 

 K.C.M.G., LL.D. ; and Reply by Dr. Yorke. 



[Received and Read March 18, 1913.] 



Although Sleeping Sickness has been recognised as a disease on 

 the West Coast for nearly two hundred years, human trypano- 

 somiasis was unknown in Nyasaland and in the greater portion 

 of Rhodesia until 1908. At the end of that year the first case of 

 the disease was found in Nyasaland, and during 1909 and 1910 a 

 considerable number of cases were discovered amongst the Euro- 

 peans and Natives living in Nyasaland and Rhodesia. This state 

 of affairs was not easy to understand, as the particulai' tsetse fly, 

 Glossina jmlpcdis., which is known to transmit Sleeping Sickness 

 in other parts of Tropical Africa, has not been found in these 

 counti'ies. 



In 1910, it was shown that the parasite causing the disease in 

 Nyasaland and Rhodesia differed in certain respects from that 



* Communicated b\' Guy CHETwy>'D, F.Z.S. 



