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Gr. L. PURSER 
commences. The nuclei at the periphery begin to take up a 
position with their long axes tangential to the organ ; the 
cells containing these will form the capsule. External to 
these the cells form a rather compact connective tissue, and 
within them the splenic tissue is but little more differentiated, 
but its spaces are, of course, venous sinuses. 
The alimentary canal between Stages XXXI Y and XXXY 
undergoes a considerable amount of remodelling (I use the 
word in the same sense as Professor Graham Kerr, ‘ Quart. 
Journ. Micr. Sci./ vol. liv, p. 484). Whereas the first turn 
of the intestine has up to now been very prominent and has 
caused the embryo to be rather tadpole-like in shape, at this 
time there is considerable shrinkage in this region so that 
there is but little bulging exteriorly (vide Keibel’s f Nor- 
mentafeln/ vol. x). The result of this is that the relative 
positions of the organs in connection with the foregut and 
the anterior portion of the intestine are altered. The foregut 
itself is rotated so that the spleen lies laterally anteriorly and 
ventro-laterally posteriorly on its right side : the dorsally 
placed wall of that part of the intestine projecting in front 
of the pyloric valve shortens, so that the three pancreatic 
buds become fused together and the bile-duct opening comes 
to lie just behind the posterior end of the spleen, a very 
marked difference from its earlier position : the pancreas 
extends forwards under the posterior half of the spleen, but 
gradually retreats further back as development proceeds. 
The histology also has advanced, although the tissue is still 
very condensed. The trabeculae are developing, as will be 
seen by examining fig. 4, but the cells, except for their arrange- 
ment, are indistinguishable from the rest of the mesenchyme. 
By Stage XXXYI, the last one examined, the organ has 
become very well-marked and obvious in sections, but it 
never becomes so in dissection, because it remains embedded 
in the sheath of the foregut. It is just over 1 mm. long, and 
its greatest diameter, towards its posterior end, is about a 
third of this. 
The first turn of the intestine has shrunk still more, so 
