SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia), 



MICEOSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA, 



a. Embryology, f 



Some Problems of Reproduction .} — Marcus Hartog points out 

 that the term "fertilisation" as actually used is too ambiguous for 

 scientific precision. In its first and older sense it denotes the starting 

 into active cell-life and multiplication of a resting-cell, and should pro- 

 perly be regarded as one case of germination. In its second sense, 

 regarded now-a-days as the " strict " sense, it denotes a process of 

 cellular (or nuclear) fusion, and is better designated as " syngamy." 



Syngamy is not necessarily associated with germination ; on the 

 contrary, in the most primitive types the cell freshly produced by 

 syngamy (the zygote) passes into a condition of rest, or gives rise only 

 to a limited brood of resting-cells, which will only germinate after the 

 lapse of time and under favourable conditions. The formation of a 

 membrane round the oosphere at the onset of syngamy in Metazoa and 

 Metaphyta is probably the last trace of this, the original consequence 

 of syngamy. 



Syngamy includes internal karyogamy and merogony, as well as the 

 pairing of separate individual cells. It seems possible that in the 

 Alcyonarians the oosphere is non-nucleate, and that the nucleus of the 

 oosperm is exclusively male, as in that produced by merogony. 



Progamic cell-divisions come under three formulas : 



(a) Gametes are morphologically equal to zoospores, and are there- 

 fore produced by multiple cell-divisions. 



(b) No tissue-cell ever becomes directly transformed into a gamete. 



(c) Karyogamy (with the possible exception of the Basidiomycetes) 



* 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, 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, 

 butalso those dealingwith Evolution, Development, Reproduction, and allied subjects. 



X Quart. Journ. Micr. ScL, xlvii. (1904) pp. 583-608. 



2 N 2 



