MAMMALIAN CESTODES. 19 
the state of contraction of the two examples could account for 
the plain lack of resemblance shown in the various figures 
referred to. Moreover, the suckers are very much smaller in the 
new example of Urocystidiwm, and by no means so prominent as 
are those of Urocystidium gemnuparum. So much then for the 
scolex of this worm, so far as it can be seen by a mere inspection 
of the uninjured worm. I have made a series of transverse 
sections through the scolex after the above figures were drawn, in 
order to elucidate further the structure of this part of the body. 
In spite of the apparent differences enumerated above, I cannot 
find any reason after a microscopic examination for regarding 
this individual as referable to a second species of the genus. The 
hooks are disposed in two rows, the hooks of each row alternating ; 
there are sixteen to each row and those of one row are much 
smaller. The apparently smaller size of the suckers is due to 
their complete retraction. It is very important to note how in- 
dividuals may appear to differ if not examined microscopically 
and when in a different state of contraction. 
In my original description of Urocystidium gemmiparum L 
gave a somewhat detailed account of what I then supposed to be 
ripe ova scattered thickly through the segments of the body, par- 
ticularly towards the end of the body. I have re-examined the 
original sections which I made, and have cut fresh sections from the 
original material in order to consider the matter afresh. A part 
of one of these sections is illustrated in text-fig. 9. It will be seen 
that, as I have already reported, the medulla as well as the cortical 
layers is stuffed with bodies closely resembling eggs. They are 
large and lie loosely in the parenchyma, being often aggregated 
into clumps. This section was regarded by two naturalists, to 
whom I showed it, as being chiefly made up by these masses of 
what appear to be eggs. I confirm my original description as 
regards the structure of these bodies. They consist of a nucleated 
cell closely surrounded by a transparent homogeneous layer, 
which I noted as being the egg-shell. I did not see the nucleus 
in all of the supposed eggs, which I carefully examined with 
high powers. This matter [am able to correct by the subsequent 
observations upon which I report here. The nucleus is present 
in all of them; but often it is seen in various stages of degenera- 
tion, culminating in freedom from granules, and thus almost 
complete transparency. In the second example of this tapeworm, 
the same cells were present and no particular description of them 
is necessary. The occurrence of the same bodies in a second 
individual led me to suspect that they were not eggs; for on the 
hypothesis of a dicecious tapeworm it might be expected that a 
male would be found. I had realised the likeness of these bodies 
to caleareous corpuscles, but had abandoned that view in deference 
_to their immense multitude, and if anything greater prevalence 
of numbers in the medullary part of the body of the worm. 
Moreover, it is usually stated that the nucleus of the cell in 
which lime is deposited, and which becomes in consequence a 
D* 
od 
