SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia), 



MICROSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 

 a. Embryolog-y.f 



Merogonic Fertilisation.^ — Prof. Yves Delage, continuing his ex- 

 periments on fertilisation, finds that a non-nucleated fragment of the 

 ovum of Echinus, Dentalium, or Lanice conchilega, may be effectively fer- 

 tilised, and give rise to a Pluteus, a Veliger, or a Trochophore respec- 

 tively. Three larvae may be reared from one ovum of a sea-urchin, and 

 a normal blastula was obtained from a 1/37 fragment. There is a cyto- 

 plasmic maturation distinct from the nuclear maturation. 



An egg-fragment of Echinus without chromosomes gave rise, after 

 fertilisation by a spermatozoon with nine chromosomes, to a larva whose 

 cells had the normal eighteen chromosomes. It seems therefore that the 

 number of the chromosomes is a property of the cellular organisation, 

 and is not dependent on the persistent individuality believed by most to 

 be characteristic of the chromosomes. 



Non-nucleated fragments seem to be fertilised more readily than 

 normal ova. Merogony favours fertilisation. It seems as if the es- 

 sential fact of fertilisation were not the fusion of nuclei, but the union 

 of a sperm-nucleus with a mass of ovum-cytoplasm. 



Since we reported on this paper, a more complete account § of these 

 remarkable observations has reached us, but the gist of the matter is 

 given above. 



Action of Inflammatory Agents on Eggs.|| — Dr. Giuseppe Levi 

 injected turpentine into the ovaries of frogs and salamanders in order 

 to observe the effect upon mature and ripening eggs. He finds that the 



* The Society are not intended to be denoted by the editorial " we," and they do 

 not hold themselves responsible for the views of the authors of the papers noted, 

 nor for any claim to novelty or otherwise made by them. The object of this part of 

 the Journal is to present a summary of the papers as actually published, and to 

 describe and illustrate Instruments, Apparatus, &c, which are either new or have 

 not been previously described in this country. 



t This section includes not only papers relating to Embryology properly so called, 

 but also those dealiug with Evolution, Development and Reproduction, and allied! 

 subjects. X Comptes Rendus, cxxix. (1899) pp. 645-8. 



§ Arch. Zool. Expe'r., vii. (1899) pp. 383-417 (11 figs.). 



H Arch. f. Mikr. Anat., lv. (1899) pp. 111-44 (1 pi.). 



