411 



IV. " On the Aquiferous and Oviducal System in the Lamelli- 

 branchiate Mollusks." By GEORGE ROLLESTON, M.D., 

 F.L.S., Linacre Professor of Anatomy ; and C. ROBERTSON, 

 Esq., Demonstrator of Anatomy, Oxford. Communicated 

 by Dr. ACLAND. Received August 20, 1861. 

 (Abstract.) 



After recapitulating the views which have been held by various 

 authors as to the means by which certain Lamellibranchiata are 

 enabled to distend their muscular foot, the authors of this paper 

 proceed to make a retractation of the opinions they put forward as 

 to the oviducal system in these mollusks in a paper read before the 

 Royal Society, February 3, 1859. But, though they have some 

 reason to agree with M. La Gaze Duthiers's views, as expressed in a 

 paper read before the Royal Society, December 15, 1859, so far as 

 the oviducal outlet is concerned ; they are not prepared to coincide 

 with that writer in denying altogether the existence in these animals 

 of an aquiferous system distinct from their blood-vessels. Upon this 

 point their views remain much the same as those they enunciated in 

 their paper already referred to, and they may be briefly summed up 

 thus. 



They hold that, side by side with, and yet distinct from, the blood- 

 vascular system in the Lamellibranchiata, there exists another sy- 

 stem of tubes forming an aquiferous tree, the trunk of which serves 

 as an outlet for the generative products, whilst many of its 

 branches spread throughout the foot into regions not occupied by 

 the organs of reproduction. This system is such an one as the peri- 

 visceral chamber has been shown to be by Mr. Hancock in the 

 * Philosophical Transactions' for the year 1858, spreading itself into 

 ramifications, some of which are, whilst others are not, in connexion 

 with the reproductive glands. The authors allow, and indeed 

 show in the way of experiment, that it is possible for the water in 

 \yhich the animal lives, to become intermingled with the blood within 

 its vessels by the route of the organ of Bojanus, and it will be seen 

 from what has even already been said, that they suppose the aqui- 

 ferous system to be fed with water by transudation of that fluid 

 from the blood-vessels. 



