TRANSACTIONS OF SECTION D. 905 



4. On a Frcyposed Biological and Physical Investigation of the English 

 Channel. By Walter Garstang and H. JST. Dickson. 



5. On the Phylogeny of the Arthropod Amnion. 

 By Arthur Willey, B.Sc. Land., Hon. M.A. Cantab. 



Until recently the formation of the amnion of the higher vertebrates was 

 wont to be explained on mechanical grounds, the embryo sinking by its own weight 

 into the yolk in the case of the Sauropsida and into the blastodermic vesicle in the 

 case of the Mammalia. In 1894 Professor Hubrecht entered a welcome protest 

 against the mechanical theory of the vertebrate amnion, replacing it by a remark- 

 able theory as to the phyletic origin of the amnion.' 



Owing to lack of data no analogous theory has hitherto been possible with 

 regard to the amnion of insects. If it were found that a common principle 

 governs the theories applied to the explanation of these similar but not homolo- 

 gous structures, the one theory would be an important complement of the other. 

 The embryos of a new species of Peripatus which I found a year ago in New 

 Britain, and have recently described,'^ seem to me to supply the material necessary 

 for coping successfully with this problem. 



These embryos, for a full account of which my memoir should be consulted, 

 possess a large trophic organ, the ectoderm of which consists of glandular absorbent 

 cells adapted for the intra-uterine nutrition of the embryo. This ectodermic layer 

 may be called the trophoblast. 



The theory, which I shall develop fully in a forthcoming paper,^ seeks to prove 

 that the glandular trophoblast arose in adaptation to a viviparous habit acquired 

 by a terrestrial descendant of an aquatic ancestor, and that this became transformed 

 into the non-glandular procective envelope, known as the serosa, in correlation 

 with the secondary deposition of yolk-laden eggs. 



As the amnion of the insect egg is subsidiary to the serosa, and the latter, 

 being a direct derivative of the blastoderm, is the older structure, the theory which 

 will adequately account for the serosa will, in its general terms, account equally 

 for the amnion. 



6. On the Micro-chemistry of Cells. By Professor A. B. Macallum. 



7. A Case of Protective Resemhlance in Mice. By Dr. H. L. Jameson. 



8. Final Report on tlie Life Conditions of the Oyster, formal and 

 Abnormal. — See Reports, p. 559. 



9. Interim Report on Zoological Bibliography and Publication. 

 See Reports, p. 558. 



10. Remarks on the Report of the International Zoological Congress 

 on Nomenclature. By Rev. T. R. R. Stebbing, F.R.S. 



k 



' A. A. W. Hubrecht, ' Die Phylogenese des Amnions und die Bedeutung des 

 Trophoblastes,' Vcrh. Kon. Akad. van Wetenschaj)pen, Amsterdam, 1894. 



■■' A. Willey, ' The Anatomy and Development of Peripatus nova-hritannice,' in 

 Zoological Resulti, &c., Cambridge University Press, 1898. 



' To be published in the Quart. Journ. of Microscopical Science. 



