Mr C. Collier on the Sea-Slug of Iiidia. 49 



of my investigations. A large vessel can be traced from the 

 summit of the membranous expansion, close to the entry and 

 termination of the intestine, to the lung *, and is there seen to 

 ramify ; and from the lung arise distinct groups of vessels, which 

 unite into one, and this again immediately divides into many short 

 branches, like vasa brevia, which pass directly to and encircle 

 the contiguous intestine ; and it sends one branch upwards, 

 which may be followed to the mouth, and another downwards, 

 which is lost on the second line of the intestine. A branch, too, 

 is sent to the organs, which are, as is supposed, for reproduction. 

 This would appear to be the distribution from the lung. Now, 

 the pulmonary vessel is joined, at its origin, by another, which 

 descends, gradually enlarging, along the floor of the covering, 

 and by a vessel besides -f- of extreme tenuity, from off the intes- 

 tine at the anus, which may be traced enlarging as it recedes 

 from this point, along the whole course of the canal. This junc- 

 tion of the three vessels forms a sac between the lamina of the 

 membranous expansion, and into this sac, if I may trust my dis- 

 section, the vessels open ; but as no impelling power can be de- 

 tected, the further transmission of the fluid is not apparent. 



The nervous system is so obscure, that I confess I know no- 

 thing about it. 



Connected by a vessel with the lung and the intestine, is a large 

 mass J, constituted by a congeries of long circular worm-like 



• The lung is of a reddish-brown hue, and appears like ramifications of 

 vessels, among very loose cellular fibre, charged with fluid. 



-f The course of this vessel may be worth notice. It jjasses from the 

 mouth, enlarging to about the centre of the oesophageal or first line of the 

 canal, and then bifurcates, sending one branch under the lung to the oppo- . 

 site line of the intestine, which again bifurcates, and then completes the 

 whole course of the canal ; it empties itself, being, as was observed, of ex- 

 treme tenuity, at the anus, into the pulmonary vessel. If it be a returning 

 vein, it is singular that it should be smallest where it joins the apparent ori- 

 gin of the circulation. 



X The quantity and the form are alike in two individuals found together, 

 while the colour thus differs. Does this variation depend upon any period 

 of particular activity of the organ ? M. Cuvier considers that as an ovary, 

 and conjectures that the white filamentous bands have some relation with 

 male organs -. — " Je crob que ces sont les ovaries de ces animaux : mais on 

 observe aussi, vers leur anus, des filamens blanchatres, nombreux, seniblable 



OCTOBtR — DECEMBEn 1829- D 



