102 Messrs. Hancock and Embleton on the Anatomy o/Eolis. 
and the skin, and thence into the network of sinuses in the 
skin itself, in the latter case into the tegumentary sinuses : in 
them and in the papillse into which it is freely admitted ; it is 
more or less perfectly aerated, and thence flows into the veins 
which pass from the skin to the auricle, and which are called by 
M. Milne Edwards branchio-cardiac vessels. From what we 
have observed however on attentively examining the connexions 
of the ovarium, we are inclined to think that the whole of the 
blood does not circulate in the way above described, for we are 
pretty sure we have recognized small veins passing away from 
the sides of the ovarium and entering the skin, and we men- 
tioned above that we had, though indistinctly, made out a pair 
of veins running from the same organ to the posterior trunk 
vein that empties itself into the auricle. If these observations 
be correct, then a small portion of blood is returned to the heart 
in a way that forms an exception to the general rule, and the 
existence of veins distinct from the branchio-cardiac is established. 
These veins we presume must carry off from the ovarium to the 
heart and the skin the blood which has been supplied by the 
ovarian artery. In confirmation of these observations and of the 
inference drawn from them, we would add, that Baron Cuvier in 
his ^ Memoires,^ &c. has described and flgured in the anatomy 
of Tritonia Hombergii six veins passing from the mass of liver 
and ovarium into the skin of the side of the body, and conveying 
the blood to the branchial tufts ; and having ourselves seen some 
time ago in the same animal similar vessels passing also from 
that mass to the skin, we are the more inclined to confide in the 
observations of the Baron. 
Examinations of the heart of E. coronata have afi’orded the 
same results as we have detailed with regard to E. papillosa. 
We have succeeded in tracing nearly all the arteries in that 
species that were observed in the latter ; but the venous tubes, 
from the excessive delicacy and high transparency of the parts, 
enhanced by the minuteness of the species, have hitherto escaped 
us. From frequent observations of the above organs in E. oli- 
vacea and several other species in the living state, we are confi- 
dent that the circulatory system is as complete in these as in the 
previously mentioned species. 
In M. de Quatrefages^ account of the organs of circulation in 
Eolidina, the existence of the venous system is altogether nega- 
tived. The incorrectness of this observation we have already suf- 
ficiently proved. The two funnel-shaped auricular appendages 
of the heart described by him have been suggested most likely 
by a view of the anterior bordei’ of the auricle, and by some 
folding of the auricle itself or of the skin along the median line 
of the body. It is certain that the auricle is single, and that it 
