96 
meter. Like the cysticercoid of Hyinenolepis muia^ it lias a body and 
a tail, and may therefore be termed 
a cercocystis. The tail is rather 
long, two or three times the length 
of the body (tig. 102). As in the 
case also of H, nana (see p. 10) the 
body is a gastrula-like structure, 
with an anterior opening and a sec- 
ondary cavity formed b}^ invagina- 
tion. Likewise, a very thin pri- 
mary cavity separates the outer and 
the inner wall. The two walls are 
highly dilferentiated(ligs. 103. 101). 
The outer consists, proceeding in 
the order from without inward, of 
a thick cuticula striated radially, a 
layer of fusiform, somewhat cylin- 
drical cells, a layer of circular libers 
(muscular?), a layer of cells much 
elongated longitudinally, and final- 
ly a lamellar layer. The second 
layer is not complete, but forms 
two longitudinal bands on opposite 
sides of the body. In cross section 
the body is seen to be rather oval, 
with these two bands of cells, cut across, corresponding to the poles of 
the major axis of the ellipse (tig. KA). The inner wall is composed of 
a layer of reticular connective 
tissue, rich in cells and calcare- 
ous corpuscles, and lined with 
cuticula. The relations of the 
scolex are the same as in the cer- 
cocystis of II. nana (see p. 10); 
that is, it lies within the second 
cavit}y and is attached behind to 
the inner wall by a peduncle, 
which in this case, however, is 
thicker and shorter than in IT. 
nana. The primitive cavity is 
well defined in good prepara- 
tions; it does not extend into the 
tail. The anterior opening of 
the secondarv cavitv is verv nar- 
riG. 103.— Longitudinal section of cercocystis of 
R. diminuta: 1. ext., external wall; 1. int.. inter- 
nal wall; pr. car., primary cavity; sec. car.. 
secondary cavity. Enlarged. (After Grassi A 
Rovelli, 1892a, pi. 4, fig. 3.) 
pr.cay. 
Fig. 104. — Cross section of cercocystis of H. dimiimta: 
I.e.vf., external wall; 1. int., internal wall; pr. car., 
primary cavity; sco., scolex; sec. car., secondary 
cavity. Enlarged. (After Grassi & Rovelli. 1892a, 
pi. 4. fig. 2.) 
row and deep. The four excretory vessels form horseshoe-like loops 
in the scolex in relation with the inner wall (fig. !<>b). 
