258 ©. CLIFFORD DOBELL. 
A good deal of variation is seen in the size of the animals. 
The measurements correspond very closely with those given 
by Gabriel for “Troglodytes.” An average large-sized 
individual measures about 20 w by 14 nu. 
Inside its shell the animal’s body is roughly differentiated 
into two zones—an anterior vacuolate zone, lying immedi- 
ately behind the shell aperture, and a posterior non-vacuolate 
zone containing the nucleus. As the food particles reach the 
interior through the shell opening they appear to be digested 
entirely in the. vacuolate zone. In this zone contractile 
vesicles are also to be found sometimes, Their number 
varies, and they are not always present. No distinct parti- 
tion into. two zones—as in Difflugia, Huglypha, etc., 
occurs. 
According to Schaudinn the nucleus is surrounded by a 
chromidial mass, which subsequently breaks up to form the 
gamete nuclei—usually eight in number. I have never been 
able to find a distinct chromidial net, though the protoplasm 
in the posterior region is often very dense, and contains many 
darkly-staining granules. Possibly these are the chromidium 
in its early stages. Later stages, with gamete formation, 
have never come under my notice. 
The nucleus itself is precisely the same as in the free-living 
amceboid form. Occasionally more than one nucleus is 
present, as Cienkowski long ago noticed, 
When the cultures containing Chlamydophrys were 
allowed to dry the animals very readily encysted. . This 
happened even before the animal had developed its shell. But 
the shelled forms also encysted, the protoplasm flowing out 
of the shell-opening becoming spherical and secreting its cyst 
wall outside. ‘he shells subsequently broke up. On one 
occasion I found an animal which had encysted inside its 
shell (fig. 84), but this is very unusual. 
The cysts themselves (fig. 83) vary enormously in size. 
The smallest are about 6 in diameter, the largest 16-17 ym. 
An average size is 144. Their most striking feature is their 
thickness, which is often very great in places. They are 
