Morphologie, Befruchtung, Teratologie, Cytologie. 261 
enlarged jacket cells which project into the archegonium, and from 
cells not adjacent to the archegonium. In the latter case migration 
and fusion of the nuclei of neighbouring jacket cells occur. It seems 
possible from Jaccards account of E. Helvetica that a similar 
development of the jacket cells occurs in that species also. If such 
development is general in the genus it seems to indicate that as in 
Welwitschia a large proportion of the cells in the apical part of 
the prothallium are capable of fertilization and embryo formation. 
A. Robertson. 
Blaekman, V. H., The nature of fertilisation. (Rep. Brit. Assoc. 
York. (1906). p. 754—755. 1907.) 
The most important Step in advance as to the nature of reduction 
was made by Montgomery, in 1901, when he put forward the 
theory that in synapsis maternal and paternal chromosomes 
unite in pairs. In the life-cycle of the organism we have thus: 
Conjugation of maternal and paternal cells, somatic divisions, and 
conjugation of homologous maternal and paternal chromosomes, 
which are later separated in the reduction division. This view is in 
general agreement with mendelian results, if we assume that the 
hereditary characters are distributed among different chromosomes. 
The difficulty arises that if unit characters are sorted out by means 
of the Separation of whole chromosomes, then in such forms as 
Canna, with only a small number of chromosomes, there should be 
an extraordinarily high degree of correlation in the sorting of the 
unit characters. The process of fertilisation seems almost incapable 
of exact definition, for such reduced conditions as “apogamy” and 
“parthenogenesis” link it on to vegetative reproduction. 
A. Robertson. 
Doneaster, L., The maturation of parthenogenetic eggs. 
(Rep. Brit. Assoc. York. (1906). p. 755—756. 1907.) 
Weismann and Ischikawa (1888) described the development 
of certain parthenogenetic eggs in which one polar body only was 
produced. In these cases it is almost certain that there is no reduc¬ 
tion. But other cases have since been described in which two polar 
bodies are formed and there is apparently either a reduction or two 
equational divisions. The fate of the polar nuclei in parthenogenetic 
eggs varies greatly in different species. There is still much contro- 
versy as to whether the somatic number of chromosomes can be 
restored if the egg begins to develope with the reduced number. 
A. Robertson. 
Farmer, J. B., On the structural constituents of the nucleus, 
and their relation to the Organisation of the individual. 
(Croonian Lecture). (Proc. Roy. Soc. London. Ser. B. LXXIX. 
N°. 534. p. 446-464. 1907.) 
The more closely the cell is studied, the more irresistibly are 
we compelled to admit the supreme importance of the nucleus in 
directing and Controlling its metabolic activities. It is possible that 
certain constituents of the nucleus, rather than this body asa whole, 
may internet with the cytoplasm external to it, and so direct and 
control cellular development. Darwin, Weismann, de Vries, and 
others, have suggested the existence of particles which are respon- 
sible for the characters of the individual. It seems that the facts of 
