Utero-gestation in Trygon Bleekeri. 423 
In any transverse section of a trophonema we find the 
vestibules of some of the glands opening widely to the surface 
between transverse sections of two superficial capillaries, 
others issuing by narrowed openings between two more or less 
obliquely cut capillaries, while others again end blindly, 
being covered by a superficial capillary in longitudinal sec- 
tion, which itself lies beneath a layer of pavement epithelium. 
It may now be stated that the examination of numerous 
sections made in various planes shows that the glands are 
faintly compound, and that they consist of a collecting well 
or vestibule, into the bottom of which the short lumina of 
the true secreting bulbs open on all sides. 
A very delicate basement membrane delimits the glands in 
their bulbous portion. 
The epithelium, as above noticed, is of two kinds: in the 
bulbs it consists of large, long, broad-based tapering cells, in 
which a single nucleus lies close to the basement membrane ; 
in the vestibule or well we find short columnar or almost 
cubical cells in which the single nucleus is more central. 
The nucleus stains deeply with carmine, the rest of the 
cell, which is faintly granular, taking the stain very lightly. 
In some of the vestibules lightly stained coagula are 
noticed. 
There are other unimportant histological details; but the 
main facts which sections exhibit are that a trophonema con- 
sists essentially of a dense vascular network, encasing in its 
meshes simple glands with bulbous loculi, protected by a layer 
of pavement epithelium which is fenestrated over the openings 
of the glands. The amount of connective tissue, except at 
the very base of the trophonema, is insignificant, and the 
trophonemata are practically built of blood-vessels and 
secreting epithelium. 
It is not easy to make an exact estimate of the number of 
glands borne on a single trophonema, and the following 
calculation can only be regarded as a probable approximation. 
Taking the area of the orifice of a vestibule at an average of 
‘001 square millimetre, and, since in any one plane at least 
two glands open into every vestibule, assuming that the 
space between the vestibules occupied by superficial capil- 
laries is given up to an equivalent of vestibular orifices, and 
calculating the glandular surface of an average trophonema at 
22°8 square millimetres, we should get in each trophonema 
22,800 glands. 
