234 
Haematozoa 
the coat of this specimen was very infested with fleas 1 , but there 
were none of the small ticks which were found on other specimens. 
It is, perhaps, noteworthy that the spleen of this rat was very 
markedly enlarged, as also were the superficial lymphatic glands. This 
animal was a rover and possibly had acquired its infection from im¬ 
ported Mus rattus. The presence of more lesion than occurs usually 
with T. lewisi infections led to a working hypothesis that the annihila¬ 
tion of native rats by imported ship rats may be due to the introduction 
of trypanosomes, which, finding a “ virgin soil ” to work upon, cause 
fatal epidemics. Unfortunately all the later specimens that were 
examined proved to be free of infection. 
Out of 12 specimens examined 3 (or 25 °/o) were affected with 
trypanosomiasis. 
(3) Mus rattus. The specimens were identified at the British 
Museum, they varied much in colour from the so-called “ grey ” to black. 
The manager of the Phosphate Company, Captain Vincent, informed me 
that these rats were first introduced to the Island in December 1899 by 
the SS. Hindustan in a cargo of hay ; they had multiplied to very 
great numbers at the time of my visit 1901-1902, but apparently 
they remained about the settlement. Altogether 13 of these rats were 
examined haematologically, and six of them were found to be harbouring 
a trypanosome of similar appearance to T. lewisi. In regard to this 
parasite, the presumption is, that it was introduced. 
A species of biting fly, much like our Stomoxys caldtrans, was also 
very prevalent about the settlement and might spread infection. 
Bats. Two specimens of the large Pteropus natalis were examined 
and both had infection with a small malaria-like parasite in their red 
corpuscles. Sporulation was not taking place at the time of examina¬ 
tion. The coats of the bats were full of a louse-like parasite. Other 
means of spread of the infection is to be found in the mosquitos. I 
took three species on the Island, Culex alis (nov. sp. Theobald) being 
a new one, G. fatigans (only few specimens seen) and Stegomyia scutel- 
laris which was very common and active during the day ; the activity 
of the latter during the sleeping period of the bats would favour their 
attack. 
Birds. The small ground pigeon, Chalcophaps natalis , was examined 
1 Loernopsylla nesiotes sp. nov. (Jordan and Rothschild, Parasitology, vol. i. p. 1. 1908). 
The Hon. N. C. Rothschild has kindly informed me that all the specimens I obtained from 
M. macleari were of this peculiar species, so that an interchange of fleas from ilf. rattus is 
not proven. 
