576 SUMMARY OF CURRENT RESEARCHES RELATING TO 



fundibulum, to which the germinal surface is at the same time approxi- 

 mated. In Bradytheria, Manitheria, platyrrhine monkeys, anthropoid 

 ;ipes, and man, none of these three methods can be said to be followed. 

 Here a number of factors co-operate, but in what precise way we do not 

 yet know — the erectility of the fimbriae, their active muscular move- 

 ment, the ciliary currents of the tube epithelium, and the configuration 

 of the vicinity of the ovary. 



Vitellogenous Layer and Mitochondria in Ova of Mammals.* — 

 0. van der Stricht finds that the vitellogenous layer seen in the ova of 

 guinea-pig, bat, man, etc., includes an aggregate of mitochondria, chon- 

 dromites, and even pseudo-chromosomes, which are morphologically 

 comparable to the mitochondrial body described by Meves in spermatids. 



Spermatozoa of Invertebrates.! — &. Retzius points out that we 

 know only a few of the invertebrate types of spermatozoa. Among 

 Lamellibranchs, for instance, those of Anodonta have been carefully 

 studied, but how many more ? He has undertaken a study of the sper- 

 matozoa of Polychasts and Lamellibranchs. In the former he found 

 two smooth refractive spheres on each side of the insertion of the tail. 

 In bivalves and in the limpet he found the same bodies, 4-10 in number, 

 regularly arranged round the root of the tail. These probably correspond 

 to the " Nebenkern " of v. la Valette St. George, and probably contain 

 the mitochondrial bodies of Benda. During development the head is 

 surrounded by a plasmic envelope with numerous granules, and these 

 collect into the sharply defined regularly arranged "accessory nuclei," 

 whose function in the fertilisation process must be investigated. 



Phagocytic Absorption of Spermatozoa.^ — Ch. Perez describes in 

 captive male newts, kept apart from females, after the sexual period, a 

 process of phagocytic absorption in the testes which is closely similar to 

 the absorption of ova in the females. 



Transplantation of Primordial — H. Braus has made some striking 

 experiments by transplanting the primordium of a limb from one 

 Bombinator larva to another, and watching the development of the 

 graft. He finds in this a method of discovering what powers of organi- 

 sation are resident in the ingrafted primordium. Thus he finds that 

 blood and blood channels develop autogenously in the ingraft, though 

 the circulation has to wait of course for connection with the blood 

 vessels of the main embryo. There is also self-differentiation of the 

 skeleton, without dependence on the metamerism of the muscular sys- 

 tem. The independent development of muscles and nerves was also 

 followed. The author points out that there is in this kind of experi- 

 ment much opportunity of testing morphological conclusions. It is, 

 in fact, " experimental morphology." 



Development of Vascular and Respiratory Systems of Ceratodus.|| 

 W. E. Kellicott has produced a stately memoir on this subject. His 



* Verh. Anat. Ges., 1904 ; Anat. Anzeig., xxv. Erganzungsheft, pp. 138-46. 



+ Tom. cit., pp. 154-6. 



\ P.V. Soc. Sci. Bordeaux (1904) pp. 51-2. 



§ Verh. Anat. Ges., 1904 ; Anat. Anzeig., xxv., Erganzungsheft, pp. 53-66. 



|| Mem. New York Acad. Sci., ii. Part 4 (1905) pp. 135-249 (5 pis. and 106 figs.). 



