323 



Trypanosoma ingens, n. sp. 



By Colonel Sir David Bruce, C.B., F.R.S., Army Medical Service ; Captains 

 A. E. Hamerton, D.S.O., and H. K. Bateman, Royal Army Medical 

 Corps ; and Captain F. P. Mackie, Indian Medical Service. 



(Received April 30 —Read May 20, 1909.) * 



(Sleeping Sickness Commission of the Royal Society, 1908 — 09.) 

 [Plate 7.] 



This is such an extraordinary looking parasite that the Commission thinks 

 it deserves a short preliminary note, a name, and to be figured. 



The name is taken from Virgil's description of the Cyclops, informe, ingens. 

 It was first discovered in the blood of a reed-buck on February 13, 1909, at 

 Namukekera, Uganda (lat. 0° 40' K ; long. 32° 15' E.), the estate of the 

 Uganda Company, Limited ; then in a bush-buck, and lastly in an ox. The 

 wild animals and the cattle feed in the same pastures, so that it is not 

 remarkable that the oxen should become infected. 



At present it is not known what the carrier is, and this will probably be 

 a difficult thing to determine. Collections of the blood-sucking flies and 

 ticks are being made on the Namukekera Estate, and this may lead in time 

 to the discovery of the carrier. Up to the present the following list includes 

 all the blood-suckers found in this particular district : — 



Chrysops distinctipennis, Austen. Hcematopota unicolor, Ricardo. 



Stomoxys caleitrans, Linn. Hcematopota, sp. no v. 



Stomoxys nigra, Macq. Hcematopota brunnescens, Ricardo. 

 Tabanus tceniola, Pal. de Beauv. 



Trypanosoma ingens, when seen alive in a fresh preparation, moves slowly 

 and deliberately across the field of the microscope, with a fine rippling, or at 

 times a broader undulating movement. 



In stained preparations this huge trypanosome may measure as much as 

 122 microns, and even then it is lying in such a formless huddled-up way 

 among the red blood corpuscles that it looks capable of stretching out to 

 a much greater length. The other specimens figured measure 72, 77, 88, 

 and 82 microns. The breadth is 7 to 10 microns. 



The micronucleus is small and round. It measures about a micron in 

 diameter. It lies posterior to, and quite close to, the nucleus. From it, in 

 well-stained specimens, a well-marked, though narrow, undulating membrane 

 arises, which runs to the anterior extremity and ends in a free flagellum. 



The nucleus is oval in form, and lies across the body. It is situated 



VOL. LXXXI. — B. 2 B 



