314 
A TRYPANOSOME AND HAEMOGREGARINE OF 
A TROPICAL AMERICAN SNAKE. 
By C. M. WENYON, M.B., B.S., B.Sc. 
Protozoologist to the London School of Tropical Medicine. 
Plate XXL 
The trypanosome to be described in this paper was discovered in 
blood films taken from the snake Erythrolampriis aesculapii (Dumeril 
and Bibron) of tropical America. For these films I am indebted to 
Dr Leiper. In addition to the trypanosome there was present in the 
blood a haemogregarine. Though haemogregarines are very common in 
snakes, especially in the Tropics, where nearly every snake examined is 
found to harbour these parasites, the reverse is the case with trypano¬ 
somes. Several observers have recorded the presence of trypanosomes 
in snakes but hitherto no one has given an accurate description of one 
of these either in the living or stained condition. Indeed our knowledge 
of the trypanosomes of the whole group of reptiles is very limited when 
compared with other groups of Vertebrata. On this account it seems of 
interest to place on record the characters of this trypanosome as it 
appears in the blood films mentioned above. 
In the forthcoming third volume of Reports of the Wellcome Research 
Laboratories, Khartoum, I have described under the name of Trypano¬ 
soma najae a trypanosome of the spitting cobra Naja nigmcollis. The 
trypanosome of the cobra was only met with in wet films and in spite of 
pi'olonged examination of many stained films not a single example of 
the stained trypanosome could be found. 
In the present instance only three stained films (Leishman stain) of 
theb lood of Erythrolamprus aesculapii were available and the appear¬ 
ances of the trypanosomes in these films are as follows. 
Two main types can be recognised and as with many other trypano¬ 
somes these may be distinguished as the wide and narrow forms. The 
