284 MR. R. ASSHETON ON THE F@TUS AND [June 6, 
stated above, had been separated from the wall of the uterus, so 
although shown im sié#w in the figure it must be understood that 
the two parts were not together in my specimen. The line 8 
marks the boundary between the two. 
On the outside I have drawn in outline the muscle coats 
(M) of the wall of the uterus. 
Within this, and seen only near the centre, is the trophospongial 
tissue alluded to above (TS), while towards the peripheral parts 
the thin layer of detritus can be seen at D, composed probably of 
both maternal and foetal tissues. 
Text-fig. 44. 
A section through the junction between trophoblast and trophospongia of Acomys. 
T. Trophoblast. Ts. Trophospongia. EP. Pseudoepithelium of trophoblast. 
EP’. Pseudoepithelium of trophospongia. MCH. Maternal blood. 
Everything within this line formed by the detritus layer on 
the outside and the trophospongial layer at the centre is probably 
foetal in origin, except the maternal blood, which is extravasated 
and flowing in channels excavated in the ‘foetal trophoblast. It 
must of course be remembered that this description is an interpre- 
tation of a single stage based upon the known facts in closely 
allied forms (ref. Duval, Robinson, Jenkinson), and not upon the 
study of the actual development in this genus. 
