54 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
actively motile, long and thin trypanosome. There were two to three of these 
parasites to a coverslip preparation. The movements of the parasite were so energetic 
that it was difficult to obtain an idea of its structure in the fresh state. The 
undulating membrane was seen to extend nearly the whole length of the parasite, 
and by its rapid screw-like movements to cause the organism to move in a spiral 
manner in and out among the red cells. 
In stained preparations the average length of the parasite, excluding the free 
flagellum which is seen with difficulty in many specimens, is 56-8 i*. Its width at the 
macronucleus is 3*5 fx. The distance between the micronucleus and the centre of 
the macronucleus is on an average 6*5 m- Measurements taken from the tip of 
the posterior end of the body to the micronucleus averaged 7 m- 
Though this parasite is much smaller than the larger parasite just described, 
the relation ot die micronucleus to the macronucleus and the relative sizes of the 
flagellum bearing and posterior portions of tie body lead us to believe that it belongs 
to the same species. The following resemblances are noteworthy with regard to the 
structure : — The smaller parasite has the same feebly staining macronucleus extending 
the whole width of the organism, and the same oval-shaped micronucleus as the 
larger form. The undulating membrane is comparatively narrow as in the larger 
parasite. The most noticeable structural difference between the two parasites is that 
in the smaller one it is the portion of the body anterior to the macronucleus 
which is more markedly striated. Other differences are as follows : — The striae in 
the smaller parasite appear as longitudinal white lines broken at fairly even 
intervals. It has no granules posterior to the macronucleus and no chromatinic 
dotted line between micro- and macronucleus. It is possible that the larger parasite 
mav represent an early stage of reproduction. 
Trypanosomes in Tortoises 
Two tortoises obtained from the marshes at Cape St. Mary, out of several 
examined, contained trypanosomes in their blood. Their blood was constantly 
examined during a period of three months, but only occasionally were parasites seen, 
and then only in small numbers. Two varieties were observed. One was a long 
thick form, the other, short and slender, possessed a comparatively broad undulating 
membrane which extended the whole length of the organism. 
The few parasites seen in stained films of blood from these tortoises have not 
been sufficiently perfect to permit their detailed description. Our notes on their 
morphology are therefore reserved until further material is obtainable. 
Trypanosomes in Birds 
Trypanosoma johnstoni. — New } species. 
This trypanosome was found in the blood of a species of small bird (Estrelda 
