some curious facts respecting the walrus and seal , 237 
elude this letter, is the peculiar structure of the funis and 
placenta of the seal : for this specimen I am indebted to Lieu- 
tenant Griffith, who, during the last voyage, met with it in 
a seal that was caught. He took out the foetus and part of 
the uterus, and brought them home preserved in brine. The 
preservation of the parts was so complete, that the vessels 
admitted of being minutely injected. 
The placenta in this animal has the following peculiarities : 
the trunks forming the funis are not twisted together ; their 
whole length is nine inches ; three inches from the placenta 
they begin to give off branches, which freely anastomose with 
one another ; these branches are connected to the placenta 
itself by three membranous folds, like so many mesenteries ; 
between these folds the blood-vessels are conveyed to the 
substance of the placenta, on the surface of which they ramify 
to a great degree of minuteness. This structure will give a 
greater facility than common to the circulation through the 
placenta, which makes it an object of enquiry, whether the 
same peculiarities exist in other marine animals. The draw- 
ings of the biliary ducts, and of the placenta, were made by 
Mr. Rose, a student in surgery under me at St. George's 
Hospital. 
I am, dear Sir, yours truly, 
EVERARD HOME. 
Sackville Street, 
Feb. 11,1824. 
