F. J. Meggitt 
399 
the necessarily artificial conditions under which the infected animals 
must be kept may quite conceivably react on their health to such an 
extent as to render them an impossible host for any normal parasite. 
It, can therefore be seen that the result obtained cannot by any means 
be considered as conclusive, but that many more experiments are 
necessary before it can be accepted. 
Davainea cesticillus Molin. 
Occurrence. Warwickshire. I have only found this species three 
times. One fowl contained three specimens and numerous D. dubius, 
and the other two only contained one specimen each. 
Attachment of Scolex. The apex of the rostellum (PL XXI, fig. 24) is 
inserted into the centre of one of the intestinal villi as far as the hooks, 
pushing the tissue before it. As soon as the hooks touch the villus 
they insert themselves into its walls. The rostellum is then retracted 
to its fullest extent, and at this stage has a small terminal depression. 
Degeneration of the intestinal tissue around the apex of the rostellum 
next begins, a small space communicating with a capillary being formed. 
From this stage onwards the intestine becomes highly vascular, the 
villi becoming so suffused with blood as to have a distinct reddish 
tinge when seen with the naked eye. In the cavity of the villus around 
the rostellum can be seen fragments of degenerating intestinal tissue 
and numerous blood corpuscles, some entering the small terminal 
depression and all clustering closely round the apex. In all cases the 
nuclei of the intestinal cells persist longest, the protoplasm on the other 
hand is absorbed rapidly. Attachment is by the rostellum only, for 
although sometimes degenerating tissue can be seen in the cavity of 
the suckers, this is merely accidental, the suckers having no part in 
the attachment. 
The highly vascular state of the intestine and the intimate con¬ 
nection between the Cestode and the intestinal capillaries seem to 
indicate that the parasite obtains part, at least, of its food from the 
blood. 
Excretory System. The excretory system is almost identical with that 
of D. dubius, consisting of four longitudinal vessels and two circular 
commissures connecting them in the anterior part of the scolex. From 
the more anterior commissure, one branch at least is given off to each 
sucker. 
Genital Organs. Investigations of the genital organs fully confirm 
Ransom’s ( 10 ) account. 
