Zoological Society. 507 
elevation of the Alps, and the dispersion of the erratic blocks ; and 
that it is so intimately mixed up with the subject of a general dimi- 
nution of the terrestrial heat, that a more profound acquaintance 
with the facts noticed in this paper will probably modify the opinion 
entertained respecting it. 
ZOOLOGICAL SOCIETY. 
March 10, 1840.—Professor Owen in the Chair. 
A paper by G. Gulliver, Esq., entitled ‘ Notes on the Ova of the 
Distoma hepaticum, and on certain Corpuscles obtained from the ge- 
nera Cysticercus, was read. 
The physiology of the Common Liver-Fluke is extremely interest- 
ing, on account of the connection which this parasite has with a very 
frequent and fatal disease of that useful animal the sheep. 
*« If we obtain,” says Mr. Gulliver, ‘‘from the bile-ducts of the 
sheep some of the larger ova of the entozoon, and subject them to 
careful examination, it will be found that the cyst of the ovum pre- 
sents a very clear outline, the continuity of which is uninterrupted, 
except at one end, where a well-marked operculum may be seen, as 
represented in the drawing. 
«<The size of these ova differs considerably ; their average length 
is about 45th of an inch, and their breadth z)5th. 
«« The interior of the cyst is occupied by granular matter, often con- 
tained within secondary and more delicate cysts or cellules, generally 
of a circular figure, and occasionally having within them a third still 
smaller cyst. ‘The diameter of the latter is about z7/,9th of an inch, 
and of the secondary cysts ;4,5th of an inch is a common size, 
although their magnitude is very variable. The granules within the 
cells or cysts also differ much in size, but they are very commonly 
about go/5pth of an inch in diameter. 
“‘ When the ova of the Distoma are compressed forcibly, the oper- 
culum is lifted up, or even separated entirely, and the granular mat- 
ter extruded, with its containing cells or cysts generally broken. 
“The operculum does not appear to exist in the smaller and im- 
mature ova. ‘The drawing No. 2. represents this in some ova ob- 
tained from the uterus of the Fluke. 
** Whether what is commonly called the ovum of the entozoon, 
may not be a cyst containing numerous ova within it, and furnished 
with an operculum, to allow of their extrusion when mature, and fit 
for propagation, appears to me to be an interesting question. At all 
events it should be ascertained if the cysts be discharged with the 
dung of the diseased sheep, whether the granules have escaped or 
not, and whether they are to be found in the pasturage of those lo- 
calities, where the entozoon is sometimes known to be propagated 
so quickly as soon to infect entire flocks of sheep. 
“1 could never see anything like a small fluke in the outer cyst, 
at any period of its growth, although the operculum was often ob- 
served just ready to open and give exit to its contents, as above de- 
scribed. 
