91 
Fig. 89. — Proglottids of H. diminuta from pos- 
terior portion of strobila. Enlarged. (After 
£. Parona, 1884. fig. 7.) 
tube from the seminal receptacle, then turns toward the ventral 
surface and backward, and in the midst of the complex of cells, known 
as the shell gland, is joined by the duct from the yolk gland. The 
shell gland {s. g.. tigs. 80, 81) is a little rounded mass which lies between 
the right and left lobes of the ovaiy. The yolJc gland {y. g., tigs. 76, 
80-82) is lenticular in shape and situated on the ventral side of the 
shell gland and somewhat more x^os- 
teriorly. With resjiect to the main 
body of the ovary the yolk and shell 
glands are x^osterior (caudad). 
From its x^oiiit oi union in the 
shell gland with the yolk duct the 
oviduct turns forward and emx^ties 
into the uterus on the dorsal side 
of the anterior x^art of the ovary 
(hgs. 80, 81). The uterus at first is 
siinx^ly a transversely elongated mass 
of cells without a cavity, but as it 
develox^s becomes hollowed out and 
the tube thus formed grows in various directions, sending out diver- 
ticula and increasing in size generally so as to gradually fill ux^ x^i’ac- 
tically the entire proglottis. After the uterus begins to grow actively 
the ovary quickly disax^x^ears. The yoke gland, however, remains 
apparent for a long time. According to the degree of develox)nient 
which the uterus has reached it is evident that the apx^earances will be 
somewhat different. Zschokke (1889). for example, has described a 
condition (fig. 81) in which 
the uterus has the form 
of two transverse canals 
uniting at one side so as 
to form a loox^, the two 
limbs of which are also 
connected at various other 
XDoints. Grassi (18881) no- 
ticed in sections of seg- 
ments in which the uterus 
had not reached its final 
develoxmient, that it ax^- 
X^eared as a large number of cavities of various sizes communicating 
with one another (figs. 82, 83). 
As the uterus grows the diverticula become crowded together, and 
the eggs form a more or less comx^act mass occux^^dng nearly the whole 
segment. The adult uterus, at first sight ax^parently a simxfie sac filled 
with eggs, is thus seen to be more comxffex; its cavity, although contin- 
uous, is broken iq) by incomxffete partitions, and by innumerable x^ro- 
Fig. 90.— Proglottis of II. diminuta containing fully developed 
ova, rendered transparent Avith potash. Enlarged. (After 
Grassi. 18881, pi. 11, fig. 15.) 
