MAMMALIAN CESTODES, 
there are no reasons for the belief that the budding which I 
formerly described was in any way abnormal in the species. 
For it seems to me to be possible, though, as I shall point out 
later, by no means certain, that the three maggot-shaped worms 
represented in text-fig. 1 may be looked upon as newly liberated 
buds, perhaps being derived from the very long specimen (text- 
fig. 1 A) which has since ceased to produce buds. This latter 
specimen measured 83 mm. in length by a greatest diameter of 
35mm. This greatest diameter was at one end of the body; at 
the other end it measured only 2mm. There were intermediate 
widths in different regions. Although the greater width of one 
end of the body suggested that this was a bladder such as I 
described in the original specimen, the segmentation was observed 
to be continuous here as elsewhere. 
The same text-figure (text-fig. 1) illustrates the three younger 
asexual forms, which were of varying size, the largest being 
presumably the eldest. In any case I have found that the inter- 
mediate sized specimen is older than the smallest. The largest 
measured 9 mm. in length by 4mm. in diameter. The propor- 
tions of the other two to it and to each other are correctly shown 
in the drawing referred to. These embryos show a segmentation 
least marked in the smallest example. It isa rather fine cross 
wrinkling ; but, as I shall show in the sequel, is a true segmenta- 
tion. When these embryos were living and rather transparent, 
they exhibited spherical spaces in the interior, visible through the 
outer wall, which are shown (and somewhat exaggerated) in the 
text-figure which has just been referred to. These cavities 
obviously suggest an internal budding of scolices as in Cenurus, 
etc.; but it is not by any means clear that they are of that 
nature. 
I examined the smallest of these three young worms by means 
of a complete series of transverse sections, and the middle-sized 
one in longitudinal sections; the structure has been compared 
with that of the fully grown asexual worm described in my earlier 
paper upon Urocystidiwm. I have, however, made some fresh 
sections of the fully grown asexual worm for the purposes of this 
comparison. The structure of the very immature maggot-like 
larvee explains certain features in the structure of the fully grown 
asexual form which I was formerly unable to explain. I shall, 
however, preface these comparisons by a detailed account of 
§ Lhe structure of the Young Plerocercoids. 
As will be seen later, the separation of these from the more 
advanced stage of the sexless worm is purely arbitrary. But, as 
there is an hiatus in- point of size and general appearance, it is 
convenient to treat of them alone. Pstraye 
I use the term ‘ Plerocercoid” in: the loosest. way, for an 
immature tapeworm which can be referred to: neither the (ysti- 
cereus nor Piestocystis type. Indeed it cannot be referred with 
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