394 Linnaean Society. 



2. With both transverse nervures united with the marginal one. — 

 Example S. stramineipes, Klug. 



3. With one discoidal cell. — Example S. Robinsoni. 



4. With no discoidal cell. — Example S.fuliginosa, Schrank. 

 And he further observes that the variations in the position of the 



nervures, and in the magnitude of the cells, will also be found very 

 useful in identifying the species. 



February 5. — William Yarrell, Esq., V.P., in the Chair. 



Read the conclusion of Mr. Huxley's paper " On the Anatomy of 

 Diphyes, and on the Unity of Composition of the Diphyidee and Phy- 

 sophoridce," &c. 



Mr. Huxley, whose communication was written at sea, commences 

 his memoir by a brief abstract of previous investigations of the family 

 of Diphyidee, chiefly derived from the works of Lesson and Will, in 

 the absence of other books of reference. Of all the authors referred 

 to, he observes, there is not one except Will, who has given any but 

 a very superficial account of the family. So far even as the nata- 

 torial organs are concerned, it is but rarely that a description is 

 sufficiently detailed and accurate not to fit two or three species with 

 equal ease, while the minute internal organs have fared still worse. 

 By all, the important fact of the gemmiparous generation of these 

 animals is overlooked ; by all, except Will, the demonstration of the 

 generative organs is omitted, and even he mentions with some doubt 

 the male sac only ; and lastly there is no attempt made by any of 

 them to trace the various organs through their development, or to 

 establish on the ground of anatomy the natural affinities of the 

 group. To these latter points, Mr. Huxley states, that his attention 

 has been chiefly directed during a voyage of some months through 

 the South Atlantic and Indian Oceans, in the course of which he has 

 examined several genera both of Diphyidee and Physophoridee, with 

 as much care and attention as the inconveniences of ship-board 

 would permit. The results are given under the following sectional 

 divisions, viz. : 1. a description of the diff"erent species examined ; 

 2. their anatomy; and 3. a comparison oi Diphyidee and Physopho- 

 ridee. Under the first head Mr. Huxley describes four species of 

 Diphyes, one of Calpe, one of Eudoxia, one of Aglaisma }, and one of 

 Rosacea. He then enters at length into the anatomy of the different 

 parts of the body, under the several heads of the common tube ; the 

 natatorial organs and the duct connecting their cavities with the 

 common tube ; the nuclear piece or bract and its sacculus ; and the 

 polypoids, each consisting of a stomachal sac, a prehensile organ and 

 a generative organ. Although generative sacs were found by the 

 author in all the genera examined by him, it was only in Eudoxia 

 and Aglaisma Q) that he procured unequivocal evidence, by the pre- 

 sence of ova, of their real nature. No unequivocal male organs were 

 observed, although the so-called " entozoa " of Will were frequently 

 seen swimming about in the cavity of the young generative organs. 

 But they were not more abundant in these situations than in the 

 stomachal sacs, common tube, &c., and their dissimilarity to true 

 spermatozoa is too great for any conclusions to be founded on their 



