11074 THE NORTHERN MICROSCOPIST. 


for this reason, it largely assists in connecting the individuals to 
each other, strengthening and maintaining the close opposition 
which is necessary for this purpose. 
The nervous system is very suppressed, only a few nerve fila- 
ments in the region of the head having been made out. 
Of the crown of hooklets previously referred to, they vary in 
number much; some possessing only twenty-four, others several 
times this quantity. In structure they are the hardest organs pos- 
sessed by tzeniz, being composed of chitine, that dense and 
insoluble substance which forms the outer covering of the beetle. 
Scattered through the soft groundwork of the community, but 
more particularly at the attached extremity may be observed a 
number of shining particles which are composed of lime; on 
further examination of the tape-worm colony a number of small 
projections are observable, usually one at the margin of each seg- 
ment, though sometimes there are two, and they may be placed 
between the margins. These elevations are the reproductive 
papilla ; on each of them are two orifices, one communicating 
with the male and the other with the female reproductive system ; 
from this we observe that each segment or individual is bi-sexual, 
or hermaphrodite, and indeed in those species which possess two 
reproductive papilla, there is a double set of these organs in 
every segment. : ; 
The generative process may be described thus :—A germ passes 
from the ovary along its duct to the uterus, where it meets with 
the spermatozoa which have traversed to this point ; then a single 
male and female element unite, and by a vital process form a new 
organism—the embryo, which becomes surrounded by an appro- 
priate quantity of the yelk, and the whole is then enveloped in a 
secretion from the uterine walls, thus forming an egg. Two other 
projective layers are added as the egg passes onward, and it finally 
escapes at the genital pore. To this brief outline I may add that 
it is generally supposed that the male organ does not impregnate 
that of the opposite sex in the same segment, but that the union is 
between those of adjoining segments. 
Each mature zooid or segment will contain some 30,000 eggs, 
and some Teenize are composed of as many as 1,250 segments, so 
that the aggregate number of eggs they are capable of producing 
at one period or growth is enormous; but to this we must remem- 
ber that other segments are being continually reproduced by 
budding from the posterior extremity of the first zooid (the head), 
and it is thus that when once the head is attached to the bowel, 
that by a non-sexual process the remainder of the colony are 
evolved ; and when by medicinal agents we effect the removal of 
the entire colony, except the head, that from this organ the whole is 
again and very quickly reproduced. The buds, at first very ill- 


