Miscellaneous. 159 
ripe egg by means of hot water, it appears to be covered with small 
rounded areas, which are possibly the impressions of the follicular 
cells. No distinct pores could be detected in it, but when wrinkled 
it appears to be vertically striated, which may argue in favour of 
their presence. 
For some time before oviposition the pleopods appear to be filled 
with a milky-white substance. This appearance is caused by the 
distended condition of the cement-glands, to the activity of which 
the secretion which forms the secondary egg-membrane is due. If 
the cuticle is removed from a pleopod at this time the tissue is seen 
to be studded with very minute, round, whitish bodies—the cement- 
glands. They are most abundant over the posteriorly directed sides 
of the lamine, and extend up into the stalk. It is noticed also, in a 
lobster “in berry,” that it is upon this side of the swimmeret that 
the eggs are mostly attached. JI have found the glands in the five 
anterior pairs of pleopods only ; but it is possible that they may 
‘ occur in the telson, the uropods, and epimeral regions. The glands 
occur singly or in clusters, and are closely crowded along the thick- 
ened edges of the lamine. 
Sections show that the gland is composed of a very delicate sheath 
of connective tissue aud a simple epithelium consisting of tall pyra- 
midal cells. The polygonal base of each cell occupies the periphery, 
at which a large round nucleus is situated, and the apices of the 
cells meet near the centre of the gland, the lumen of the organ 
being at this time very slight. It is almost impossible to detect in 
sections the opening of the gland to the exterior, but it is quite 
probable that each gland opens separately. Cano describes these 
glands in numerous forms as bottle-shaped structures, the necks or 
ducts of which open to the exterior through pores in the cuticle. 
Pores can be shown to exist in the lamina of the pleopod by re- 
moving the tissue by caustic potash and distending the cuticle with 
water; but pores of the same kind also exist in the appendages of 
the male, where no cement-glands occur. I cannot at present say 
how the pores are distributed on the surface of the cuticle, but it is 
probable that they are not confined to any particular area. 
If the glands are examined shortly after oviposition, they show a 
remarkable change in structure. The glands are enlarged and the 
epithelial cells have the appearance of degeneration, their nuclei 
presenting every stage of fragmentation, from the condition of minute 
chromatin-particles, which fill almost the entire gland, to deeply 
stained round granular masses, which are much larger than ordinary 
nuclei. Under these conditions cell-outlines are very dim and the 
lumen of the gland is not open. 
It seems quite probable that the peculiar gland-like structures 
which I have described in the immature ovary of the lobster (see 
these Circulars, no. 88) are concerned with the growth of the 
ovarian eggs. Numerous follicular cells enter these growing ova at 
an early stage, and gradually become converted into food-products. 
Their nuclei break up into very small vesicles, and finally lose all 
