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Transactions of the 
L Monthly Microscopical 
Journal. May 1, 18B9. 
elasticity of the walls ; tlie transverse section generally gives an 
oval outline, but sometimes the shape is quadrangular, this depends 
on the existence of other fine rods than the two above mentioned. 
In a small species of Pagurus, P. misanthrojpicus (Fig. 7), the 
spermatophora are of a different form and structure from the fore- 
going: in the first place they are separate from each other, the 
basal portion forming a small round disk, from the centre of which 
springs a long stalk, filled with a sort of medulla ; on the upper ex- 
tremity of this is placed the spermatophorum proper, nearly globular 
in shape. A higher magnifying power shows it to be surrounded 
by two membranes, but of this I could not be certain as I omitted 
to bisect it ; however, the outer one appears to be a continuation of 
the sheath of the stalk, the inner one being connected with the 
medulla of the same ; from the apex of the medulla appears also to 
arise a fine sort of connective tissue, binding the zoosperms into 
one mass. It only now remains to describe the development of the 
zoosperms ; having paid more particular attention to that process 
in P. Bernhardiis, I will give the details of it in that species. 
The testes of P. Bernhardus consist of a glandular part and 
an excretory duct. The glandular portion of the right testis is 
situated between the liver and dorsal surface of abdomen, rather on 
the left side, the duct crossing to the right side of the thorax, 
towards its exit at the base of the fifth thoracic limb. The glandular 
portion of the left testis is placed deeper, between the two lobes 
of the liver, and resting on the abdominal muscular mass; it is 
altogether smaller than the corresponding portion of the right 
testis. The gland is tubular, having numerous enlargements, or 
sacculi, resembling the large intestines of mammals somewhat in 
form. Its lower end is filled with mature zoosperms, which decrease 
in number towards the distal extremity, where nothing but sperm- 
cells are to be found, which on their part had gradually increased in 
number. These vary much in size and shape. If immediately that 
the animal has been kiUed by chloroform a piece of the gland is 
transferred with the utmost dispatch on to a glass slide, on which 
a drop of the blood of the animal has previously been placed, and 
then the walls are separated by needles, the cells drop out without 
themselves being touched, the field of the microscope is found 
filled with these cells, floating about either singly or in groups. 
(Fig. 8 a) At this period they are uniformly granular, and appear 
like semi-solid globules of matter, without the slightest appearance 
of either nucleus or cell-wall ; neither is there anything whatever to 
lead one to suppose that they arise from mother-cells, there being no 
appearance of a cell-wall round any of the groups. (Fig. 8 h) After 
they have remained some time in the fluid a sort of precipitation 
occurs in their interior, and a nucleus appears. This is also granular, 
and seems solid. Occasionally the nucleus is surrounded by a clear 
