SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(PEINCIPALLY INVEETEBEATA AND CEYPTOGAMIA), 



MICROSCOPY, Etc.* 



ZOOLOGY. 

 VERTEBRATA. 



a. Embryolog-y. f 



Material Basis of Inheritance.^ — F. Vejdovsky has studied the 

 chromosomes in spermatogenesis in particular, in various types : Ascaris 

 jnegalocephala, Decticus verrucosus, Diestramena mar^noraia, etc. He 

 distinguishes a slightly stainable linin and a " chromonema " of chro- 

 matin which occurs in a very delicate close spiral on the surface of the 

 chromosome. 



In karyokinesis the vesicular nucleus is formed from the chromosomes 

 only. Their linin becomes nuclear sap or enchylema. The spiral 

 thread on the chromosome forms an achromatic linin framework in the 

 resting nucleus and a residue of undifferentiated chromatin. This 

 appears as isolated granules (chromomeres) embedded on the framework. 

 In the preparation for another division, the chromomeres form new 

 chromonemas. A phase of " katachromase " leads to the formation of 

 the vesicular daughter-nuclei from the chromosomes ; a phase of " ana- 

 chromase " leads to the formation of a new chromosome generation. 

 The chromonemas always serve as the starting-point for the new 

 chromosome generation. 



Emphasis is laid on the parallel conjugation of pairs of homologous 

 chromosomes, a mingling of chromatic and achromatic substance, and 

 it is in this that the process of reduction is effected. Yejdovsky up- 

 holds the importance of the chromosomes as bearers of the heritable 

 qualities, and does not believe that this is true of the mitochondria. 



Nucleus and Cytoplasm in Inheritance. § — Allette Schreiner dis- 

 cusses the role of nucleus and cytoplasm as vehicles of inheritance in 



* 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 pub- 

 lished, and to describe and illustrate Instruments, Apparatus, etc., 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 dealing with Evolution, Development, Reproduction, and 

 allied subjects. 



I Zum Problem der Vererbungstrager. Prag (1912) 184 pp. (12 pis. and 16 figs). 



§ Biol. Centralbl., xxxii. (1912) pp. 280-3. 



