118 MR. F. J. MEGGITT ON A 
Kraemer states that vagina and cirrus open directly to the 
exterior. My own specimens confirm the former statement. 
FTistology. 
The body is covered by a two-layered cuticle (Pl. II. fig. 12). 
The outermost layer is dark-staining and rough in outline, and 
is split up by vertical clefts into a great number of fine hair-like 
processes. The whole appearance is that of a cast cuticle. A 
similar cuticle is present in Schistocephalus dimorphus Crepl., 
and this Kiessling (9) considers to be a disintegration product of 
the underlying layer: it is probable that this is true of [ehthyo- 
tenia jilicollis also. Under this cuticle is a feebler-staining 
homogeneous layer. Acco:ding to Kraemer, there is a third layer 
(‘‘ Cutis”) underneath this: im one or two cases in my specimens 
it has appeared as though there were a third layer, but this is pro- 
bably only an optical effect. Benedict does not mention it at all. 
Following the cuticle is a layer of circular muscle-fibres, and 
then one of longitudinal muscle-fibres. Internally is a sub- 
cuticular cell-layer, composed of spindle-shaped cells, *02—028 
x ‘007 mm., drawn out into delicate protoplasmic processes 
internally, and possessing a prominent nucleus, ‘005 mm. dia., 
and nucleolvs, ‘003 mm. dia. 
The structures above-mentioned appear to vary greatly in size 
according to different investigators (Table B); it is apparent, 
therefore, that their size is a character too unstable for classi- 
fication. 
Under the sub-cuticula is the parenchyma. This consists of 
polygonal cells, with a varying diameter of -0046—008 mm., 
with nuclei ‘0023 mm. dia. ‘The cell corners interlace with 
one another to form a loose meshwork enclosing intercellular 
spaces, the meshwork being closer externally and less compact 
between the various organs. The intercellular spaces are often 
empty, but more usually are filled with a feebler staining granular 
mass which Kraemer thinks is an BEueneny product of the 
parenchymatous cells. 
Forming a regular layer under the cuticle in the more 
posterior part of the body are large numbers of rather small 
calcareous bodies. They are oval and stratified, rather like 
starch-grains. In the larval cestode they are much longer and 
not so stratified, and are scattered irregularly over the body ; 
they show very distinctly under the cuticle, and appear as if 
actually on the body surface. 
There do not appear to be any oil globules comparable with 
those mentioned by La Rue (11) in P. filaroides. If the Cestode 
be examined in water, numerous transparent bubbles may be 
seen attached to the body and gradually growing larger ; these 
may correspond to the oil globules and be due to the water 
round the specimens causing the minute invisible oil droplets on 
the body to coalesce into larger drops. 
