A. C. Coles 
39 
Gondei- has stated that Achromaticus is intermediate between the 
malaria and piroplasm parasites and Ollwig and Manteufel^ consider 
them closely related to the latter. Parasites showing division into 
four piriform parasites are very infrequently seen, but I have found 
them most clearly defined in films in which the parasites were not 
numerous. 
Films from the internal organs, heart, lung, spleen, liver, kidney and 
bone marrow were made from all the infected bats, and a few parasites 
were found especially in the lung and heart blood. 
Piroplasms in the Field Mouse—Nuttallia muris sp. n. P 
In the blood of a field mouse caught in this neighbourhood, 
April 7, 1912, in addition to the haemogregarines already described, 
I found some small unpigmented bodies situated in the red blood 
corpuscles. 
These were present only in very small numbers and were only to be 
found by careful examination. One of the most noticeable features 
about them was not so much their small size as their marked transpar¬ 
ency, and it is quite easy to go over the whole slide with an immersion 
objective and low eyepiece and miss them entirely. In fact when 
I have found a parasite and noted the exact position by the reading on 
the mechanical stage, and have further mai’ked the spot with a small 
diamond ring on the coverglass, I have irot infrequeirtly experienced the 
greatest difficulty in detecting the same parasite again. 
These intracorpuscular bodies vary in their size and shape, but by 
far the commonest is a round or oval shaped structure, which occupies 
a position just outside the centre of the corpuscle. Sometimes they are 
’ entirely on the margin and may actually project beyond the outline of 
the red cell. (Plate II, fig. 20.) 
The central part is stained very faintly a blue colour, often it is 
almost colourless. The margins are more deeply stained, in part 
a chromatin red and in part a blue tint. 
The smallest and presumably therefore the youngest forms are 
somewhat elongated oval or round, the largest are round or oval, rarely 
irregular in outline. The smallest parasites generally show a red 
stained spot at one end, and sometimes there are two such nuclei at 
opposite sides of the ring. 
The larger oval forms appear to contain more chromatin, which 
extends ^ to | round the margin. Vacuoles are occasionally but rarely 
1 See Prowazek (1912). 
