PHILOSOPHICAL 
TRANSACTIONS. 
I. An Account of the circulation of the blood in the class Vermes 
of Linnceus, and the principle explained in which it differs 
from that in the higher classes. By Sir Everard Home, Bart. 
V. P . R . S. 
Read November 7, 1816. 
Having spent a part of last August on the Sussex coast, 
where the Lumbricus marinus is met with in great numbers, 
it suggested itself as an object worthy of investigation, to 
determine the difference in structure between this worm and 
the Teredo on the one hand, and the Lumbricus terrestris on 
the other. I was the more led to this from having made my- 
self familiar with the structure of the Teredo, an account of 
which has a place in the Philosophical Transactions. 
These three different genera of worms, although they differ 
in many respects from each other, have several points of re- 
semblance ; they all destroy b}i boring the substances they 
inhabit, an action requiring great muscular power ; they take 
into their stomachs the broken down substance ; they have giz- 
zards, and red blood ; their place of residence however, being 
very different, requires that there should be peculiarities in 
. mdcccxvii. B 
