102 Messrs. Hancock and Embleton on the Anatomy of 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 papilla? 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 f Memoires/ &c. has described and figured 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 afforded 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 border 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 



