192 



with the Hydrographer's Office of the United States, so that the 

 united labours of the two greatest naval and commercial nations of 

 the world may be combined, with the least practicable delay, in 

 promoting the interests of navigation. 



The President and Council refer to the documents which have 

 been submitted to them, and more especially to the " Explanations 

 and Sailing Directions to accompany wind and current charts " pre- 

 pared by Lieutenant Maury, for a more detailed account of this 

 system of cooperative observations, and of the grounds upon which 

 they have ventured to make the preceding recommendations. 



(Signed) S. Hunter Chuistie, Sec. R.S. 



H. U. Addington, Esq. 



3. " Second Appendix to a paper entitled ' Discovery that the 

 Veins of the Bat's Wing (which are furnished with valves) are en- 

 dowed with rythmical contractility.' " By T. Wharton Jones, Esq., 

 F.R.S. &c. 



The author states that, from a microscopical examination of the 

 blood-vessels and circulation in the ears of the long-eared bat, he 

 has ascertained that, different from what he had discovered to be the 

 case in the wings, the veins of the ears are unfurnished with valves, 

 and are not endowed with rythmical contractility, and that the 

 onward flow of blood in them is consequently uniform. 



4. A paper was in part read, entitled, " Upon the Morphology 

 of the Cephalous Mollusca, as illustrated by the anatomy of certain 

 Heteropoda and Pteropoda." By Thomas Huxley, Esq., F.R.S. 

 Received March 18, 1852. 



May 27, 1852. 

 The EARL OF ROSSE, President, in the Chair. 



The reading of Mr. Huxley's paper, " Upon the Morphology of 

 the Cephalous Mollusca, as illustrated by the Anatomy of certain 

 Heteropoda and Pteropoda," was resumed and concluded. 



In the present memoir the author endeavours to determine, upon 

 anatomical and embryological grounds, the true homologies of the 

 different organs of the Cephalous Mollusca, and thence to arrive at 

 some idea of the archetypal form, as definite modifications of which 

 the existing molluscous forms may be considered to have arisen. 



The Pelagic Heteropoda and Pteropoda, from their small size and 

 extreme transparancy, are peculiarly favourable subjects for the ana- 

 tomical part of this investigation, and it is from a detailed examina- 

 tion of those systems of organs which are of importance for the pur- 

 pose that the author deduces the following conclusions : — 



1 . In the Heteropoda the intestine is bent towards the dorsal or 

 hcumal side in consequence of the development behind the anus of 

 the visceral "hernia," which is therefore called 2^ post-abdomen. 



