56 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 
I have found several stages which I believe lead up to this condition. 
Apparently the substance which is destined to envelop the nucleus first 
collects along the partition separating the body from the head of the 
animal (Fig. 13). Possibly the formation of this thick envelope is pre- 
paratory to the production of the spores. 
The posterior or body half of the animal is principally occupied by a 
highly vacuolated protoplasmic mass (Fig. 7), which has usually reached 
the state of a coarse reticulum. In this reticulum large pieces of wood 
fibre and spores of fungi are frequently found embedded. This central 
protoplasmic reticulum is completely surrounded by a granular proto- 
plasmic wall (st.gran.’, Figs. 7, 13, 15), which is continuous in front 
with the granular partition separating the “head ” from the “body.” 
The granular wall is not very thick, and passes on its inner surface 
rather gradually into the protoplasmic network; but it is more sharply 
defined on its outer surface, though even here the transition to a rather 
thick cortical layer (st. ctx., Figs. 7, 13, 15) immediately outside it is not 
very abrupt. This cortical layer is composed of finely granular almost 
homogeneous protoplasm, and is of nearly, though not quite, uniform 
thickness. Its average thickness is about the same as that of the inner 
layer enveloping the bell. 
The surface of the “ body” appears to be traversed by nearly equidis- 
tant lines, which have a slightly spiral — left-handed or læotropic — 
course (Plate 1, Figs. 1, 2). These lines appear to be continuous in 
direction with the innermost set of cilia, which cross one another at the 
posterior tip of the body, and in fact the lines are in my opinion due exclu- 
sively to the presence of these cilia, which are closely applied to, but are 
entirely free from, the wall of the “body.” Frenzel’s description of the 
condition in Leidyonella is certainly not applicable here. Frenzel (85, 
pp. 306, 307) maintains that in Leidyonella the rigid cilia arise at or near 
the anterior end of the body, but that, instead of being free throughout 
their whole length, they are fused with the peculiar cuticula which covers 
the body, causing ridges, which have a slightly spiral course (he does 
not say whether right or left, and his figures are noncommittal), and 
that they become free only as they project beyond the posterior ex- 
tremity of the body. These ridges are stated to be much more promi- 
nent in the anterior than in the posterior part of their course, But, 
whatever may be the condition in Leidyonella, the spiral markings in 
Trichonympha are not traceable forward any further than the boundary 
between “body” and “bell,” and they are not due to confluence of cilia 
with the wall of the body of the parasite. 
