616 EMBRYOLOGY OF THE TURTLE. Part III. 
fic. 2) of the kidneys are pretty far advanced. The bloodvessels (4) do not form 
a convoluted glomerulus in the end of the uriniferous tube, (a, @, @’,) but in 
a swelling situated at a certain point in its track. The cells of the wall of 
the Malpighian body are short and broad, and form only a single layer (a, a’). 
The bloodvessels in the glomerulus are very closely crowded, and tortuous. Only 
a single vessel, whether artery or vein could not be determined, was seen in 
connection with the glomerulus. 
The Wolffian Bodies. A short time before birth, the uriniferous tubes of the 
Wolffian bodies are composed of very large, irregularly polyhedral cells, arranged 
in one layer (Pl. 20, fig. 1, la, 1b) around a rather large, central channel (fig. 
1, a). In a transverse section, these cells appear broadly wedge-shaped, with the 
narrower end next to the central channel (fig. 1, la). Where the tube bends upon 
itself, the cells all converge around one point, so that the imner ends of some 
may be seen in the centre, (fig. la,) and the channel in the distance. At this 
stage, the uriniferous tubes are very long and slender, and may be very easily 
traced from the central canal, or duct, (Pl. 25, fig. 5, ¢,) to the point (a) where 
they bend upon themselves, at the parietes of the Wolffian body, and return 
to the channel whence they started. The uriniferous tubes (0) of the kidneys 
are very short and thick, and are much less numerous than those of the Wolf 
fian bodies. They also run outward, and back toward the duct, (¢,) but we are 
not sure that they empty into it. 
The Blood. About the time the heart begins to lose its tubular character, 
and the eyes and ears have become decidedly marked and conspicuous, (Pl. 12, 
fig. 6e, and p. 550,) the blood corpuscles are mere globular, minute, transparent 
cells (Pl. 19, fig. 6, 7, a, 6). This shape and size they retain for some time, 
at least until the allantois has nearly covered the embryo, (PI. 14, fig. 2, 2a,) 
and the lungs (Pl. 24, fig. 2, 2a) have become separated from the intestine, and 
begun to assume a sac-like shape. In a natural state, these corpuscles (PI. 19, 
fig. 7, a, b) are perfectly globular and transparent, and each contains a large, 
apparently granulated mesoblast attached to the wall (a). By the application of 
water, the mesoblast bursts, (¢, d, ef, g, & 7% 7,) and the whole granular contents 
come out, but still retain their globular state, and appear to have a membrane 
about them (j). From this it would seem that the apparently granular contents 
of the mesoblast constitute, in reality, an entoblast which fills the mesoblast. The 
blood corpuscles do not attain to the characteristic oval and flattened shape of the 
adult (fig. 8, @ to 7) until very late. At a certain stage, (see Pl. 15, fig. 1, 2, 3, and 
1 Fig. 7, a, b belong to a little later stage; but, tical with those of this stage, it would be superfluous 
as the blood corpuscles which they represent are iden- to repeat the figures. 
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