422 WM. CECIL BOSANQUET. 
be a different species from the one occurring in L. herculeus, 
of which the following is a brief account. 
Description, Habitat, &c—The animal is of a pure 
white colour, and quite opaque. It is rounded in form, 
generally spherical, but some individuals are of a blunt oval 
shape (fig. 1); and others, again, apparently young specimens, 
appear as flattened oval discs. They vary in size from minute 
specks to bodies with a diameter of over 1 mm. An average 
specimen measured under the microscope gave the proportions 
1:2 by'9 mm. A few individuals occurred in the hinder seg- 
ments of nearly all the worms (L. herculeus) which I opened. 
In one or two instances almost the whole body-cavity was 
filled with Gregarines. (In a number of specimens of Allolo- 
bophora fctida (?) which I examined I did not find any of 
these animals.) They lie seemingly loose in the ccelom, but I 
have found young specimens embedded in a growth of cells 
along the intestine of the worm, and cysts very constantly in 
the same position (see p. 429). 
Influences affecting Development.—Gregarines in 
different stages of development may apparently exist side by 
side in the same host, but in most cases there appeared 
a great preponderance of these in one condition, either as 
cysts, or conjugating pairs, or mature individuals, which 
fact would seem to point either to some external influence 
acting on the parasites, e.g. some alteration in the nature of 
their environment, leading them to a simultaneous change of 
state, or, as seems perhaps more probable, to a definite cycle 
in their lives in accordance with the seasons of the year— 
since I found mature Gregarines plentiful in the autumn and 
winter months, many instances of conjugation about the spring, 
while during the summer I could not find any specimens other 
than cysts and spores. 
Evidence seems wanting as to whether the well-being of the 
host is affected by the presence of Gregarines. On the one 
hand, worms of the most healthy appearance contained a 
considerable number of the parasites, while, on the other, a 
very sickly and apparently moribund worm was crowded with 
