2 Mr. F. G. Penrose on a Cysticercus 
It opens externally at its proximal extremity by one of its 
ends only. The ‘ body ’ is teenioid in its proportions, and is 
not segmented. It is about 24 inches in total length, the 
‘head’ being about the size of a hemp-seed or a little 
smaller.” 
I also showed the sections to Prof. Lankester, who gave 
me several references ; but I failed to make any thing out, and 
nothing more was done until Prof. Lankester saw a mono- 
graph on Cysticercus-forms by Dr. Monier of Lille. He im- 
mediately recognized that the worm I had cut was a Cysti- 
cercus. He lent me the monograph, of which the title is 
‘Travaux de l'Institut Zoologique de Lille et de la station 
maritime de Wimereux,’ tome ul. fascicule i., ‘‘ Essai Mono- 
graphique sur les Cysticerques par R. Monier,” and per- 
suaded me to cut some more sections, with the view of ascer- 
taining if this particular form had been described. 
Dr. Monier has fairly completely worked out the history of 
the Cysticercus-larva (C. pisiformis) of Tenia serrata, and 
gives some beautiful figures. 
He shows the early development in the liver of the rabbit, 
and describes a migration at the end of the first month 
into the peritoneal cavity. He then gives a description of a 
form soon after it has arrived in the peritoneal cavity. He 
shows how, at the time of leaving the liver, the young Cysticerce 
are at various stages of development, but that generally the 
cephalic rudiment of the future Zenza is already differentiated, 
and even that it was distinctly indicated on the twenty-second 
day after infection. 
He describes how the rudiment is at first a simple depres- 
sion surrounded by a thick bed of granular cells, then how 
the invagination increases and how at the same time there 
is cell-proliferation, that at the bottom of the invagination a 
slight dilatation forms, and at the same time an elevation 
_rises slightly to one side of the line of axis of the invagination 
from the floor of this invagination, which is the origin of the 
head of the future Tania. 
He then describes the origin of the suckers and of the 
hooklets. - 
Embryos which he has just been describing have gene- 
rally attaimed the length of more than a centimetre. 
He then goes on to describe the histological details, and 
discusses the formation of the future vesicle. 
The stage to which I have been referring is certainly 
less advanced than that of those Iam going to discuss ; and the 
next stage is also certainly more advanced. The two stages 
are illustrated at Pl. II. figs. 2 and 5. 
