some curious facts respecting the walrus and seal , &c. 241 
Plate VIII. represents the placenta of the seal, in which 
there are several peculiarities ; upon a scale of half an inch 
to an inch : the foetal surface of the placenta only is exposed. 
The funis is nine inches long, but the blood vessels are 
not twisted on one another as is common in quadrupeds ; 
and after passing three inches from the navel of the foetus, 
the vein divides into two branches. At six inches the arteries 
and veins sub-divide so as to form three distinct chords, and 
these, instead of going directly into the substance of the pla- 
centa, have doublings of membrane surrounding them in form 
of mesenteries, in which their branches are inclosed ; and 
these terminate in the placenta, rendering the surface very 
vascular. 
This surface of the placenta has a lobulated appearance : 
but the fissures do not extend to the maternal surface, which 
has throughout a granulated appearance. 
MDCCCXXIV. 
Ii 
