A. C. Coles 
19 
were fairly numerous and wei’e associated with the presence of very 
numerous intracorpuscular parasites, Achroviaticm vesperuginis, and in 
the third (1913) the trypanosomes were exceedingly rare, only five 
being found in 20 films which, however, contained a heavy infection of 
Achromaticus. 
Achromaticus vespei'iiginis was found in seven Pipistrelles, two of 
which showed a heavy infection, two were moderate and in three the 
parasites were very scanty. 
Haemamoeba, pigmented intracorpuscular parasites, were found in 
one Pipistrelle caught locally. 
Spirochaeta I found in very small numbers in one Pipistrelle 
together with a large number of Achromaticus, and in one of the large 
short-eared bats, the Noctule (Vesperugo noctida), in which it was 
associated with a Filai'ia. 
Two long-eared bats (Plecotus auritus) caught locally were examined 
but no parasites were discovered. 
Thus in the blood of 9 out of 25 bats parasites were found, and with 
one exception the infected bats came from Reading. This does not 
necessarily mean that the bats caught locally are less infected, but that 
most of the specimens sent from Reading, 13 in number, were examined 
when I had become more skilled in detecting some of these not easily 
recognised parasites. 
Trypanosoma vespertilionis (Battaglia). 
In one of the Pipistrelles sent from Reading (May 1906) I found 
a very large number of trypanosomes both in the immature and adult 
stages. 
The proportion of the different forms varied remarkably in five films 
made, as far as I can remember, from the blood taken from the heart, 
but I counted 372 immature to 428 fully grown parasites, i.e. 46'5 
were immature developmental trypanosomes and 53'5 "/o adult types. 
Ivimature Trypanosomes. These are for the most part somewhat 
pear-shaped, some oval and a few almost round. (Plate II, figs. 9, 
10 , 11 .) 
Each possesses a nucleus, centrosome and one or more flagella. The 
protoplasm is slightly granular and stains blue. The nucleus, which is 
about 2 /i in diameter, is situated either in the centre or more generally 
somewhat towards one end of the' organism. It is usually round, and 
shows little structure, except that it appears to consist of a number of 
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