594 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Structure and Development of Female Gonads of Lancelet.* — 

 The late Ludwig Neidert made a careful study of this, and the work has: 

 been completed by Adolf Leiber. An account is given of the early 

 period of gonad-forrnation and of the period of ripening. The gonocool 

 or cavity enclosed by the gonadial wall, the " Nabel " from which the 

 ovarian vessels arise, the " Narben " or cushions which surround the 

 openings of the gonocoel, and so on are described in minute detail.. 

 The process of oogenesis is described. Particular attention has been 

 paid to the blood-supply of the ovaries. 



Follicular Epithelium in Birds. f — Marie Loyez finds that in some- 

 birds all the cells of the follicular epithelium exhibit, outside the nucleus, 

 an almost spherical body of considerable size, composed apparently of 

 coiled filaments. It stains strongly with iron-hteinatoxylin, and is 

 analogous to the ergastoplasm of Garnier, the mitochondria of Benda, 

 and the pseudochromes of Heidenhain. The differentiation is well seen 

 in Coccothraustes chloris, Emberiza citrinetta, Fringilla Calebs, and 

 Parus cxruleus, while in other cases, e.g. fowl and pigeon, it was not 

 detected. 



Ovarian Ova and Follicles in Fishes4 — W. Wallace has studied 

 the ovaries of various species of Teleostean and Elasmobranch fishes, 

 with particular reference to (1) the post-embryonic origin of ova and 

 follicular epithelium, (2) yolk-nuclei and their significance, (3) egg- 

 membranes and follicular epithelium, (4) the histology of egg-absorp- 

 tion, and (5) structural changes in ruptured follicles. The paper also 

 includes a general description of the peculiar ovary of Zoarces, and 

 some data bearing on the rate of growth and comparative fecundity of 

 this fish. 



Influence of Central Nervous System on Development of Limbs 

 in AmphibiansJ — P. Wintrebert has made some interesting experi- 

 ments on Axolotl larva? (Siredon pisciformis) and on the tadpoles of 

 Rana temporaria. AVhile P. Rubin has maintained that the influence 

 of the nervous system is essential in the regeneration of parts of limbs 

 in Urodela, A. Schaper found that the removal of the tadpole's brain 

 did not hinder its general growth, and Wintrebert's results go towards 

 confirming this. He cut the nerves to the hind limb of Axolotl larva? 

 just at the time when the toes were being formed, but after G-12 days 

 one or two toes appeared normally. More extensive experiments on the 

 tadpoles of the frog gave the same result, and the author concludes that 

 in these cases the nervous system is not necessary for the growth or 

 differentiation of a limb. 



Development of Pineal Body in Amphibia.|| — J. Cameron finds 

 that in Rana, Bvfo, and Triton the epiphysis arises in the form of two 

 primary outgrowths from the roof of the fore-brain, one on each side 

 of the mesial plane ; the right outgrowth disappears at an early stage 



* Zool. Jahrb., xviii. (1903) pp. 187-240 (5 pis. and 3 figs.). 



t Comptis Rendus, cxxxvi. (1903) pp. 312-4. 



J Quart. Journ. Micr. Sci., xlvii. (1903) pp. 161-213 (3 pis.). 



§ Comptes Rendus, cxxxvii. (1903) pp. 131-2. 



|| Anat. Anzeig., xxiii. (1903) pp. 394-5. 



