ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 735 



The spindle of the ventral canal cell-division is almost entirely of 

 nuclear origin, and the chromosomes are derived largely from the 

 nucleolus. The egg nucleus contains a large amount of granular 

 material, but a chromatin reticulum is always present. This granular 

 material is largely used in the formation of the spindle of the fusion 

 nucleus. 



Fertilisation occurs about the middle of June, and two or more 

 sperm-cells may enter an archegonium, but only one fuses with the egg. 

 The sperm-cell passes through the cytoplasm of the tip of the egg, and 

 reaches and enfolds the female nucleus. The larger part of the cyto- 

 plasm of the egg takes no direct part in the formation of the embryo, 

 but is digested and iised by the latter in its growth. The first division 

 occurs after the fusion nucleus has reached the base of the archegonium. 

 Eight free nuclei are formed and arrange themselves in two tiers, the 

 Tipper of which generally contains six, the lower two ; cell walls are 

 formed, but the upper side of the upper tier is left open. This open 

 tier divides, by walls at right angles to the long axis of the archego- 

 nium into the rosette of free nuclei above and the suspensors below.. 

 The two cells of the lower tier divide at the same time by walls parallel 

 to the long axis of the archegonium, forming four cells in one plane. 

 The suspensors may or may not separate on elongation, forming several 

 or only one embryo from one archegonium. 



The author considers that Taxodium should be removed from the 

 Taxodiese to the Cupresseas, leaving Sequoia, and perhaps other genera of 

 the same tribe, to be included in a tribe of their own under another 

 name. 



Morphology of Angiosperms.* — The present volume forms the 

 second part of the work on Seed Plants, the first part of which, by 

 the same authors, appeared in 1901. Part I. dealt with the Gymno- 

 sperms ; in Part II. the Angiosperms are treated on somewhat similar 

 lines. In the interval between the times of publication of the two parts, 

 views on the relationship between the two great groups of seed-plants 

 have become somewhat modified. The tendency of the results of recent 

 work is to emphasise the distinctness of the two groups, and, especially 

 by virtue of the light thrown on the Cycadofilices, to bring out more 

 strongly the affinity of Gymnosperms with the Pteridophyta. The 

 origin of the Angiosperms still remains obscure, and the light thrown on 

 the phylogeny of the other group seems but to emphasise the isolation 

 of the larger division of seed-plants. Messrs. Coulter and Chamberlain 

 express their conviction that such an association of the two groups as 

 was contemplated would help to emphasise a relation which does not 

 exist, and that Gymnosperms and Angiosperms should be treated as 

 independent groups co-ordinate with Pteridophyta. The two parts of 

 their work are therefore to be regarded as independent volumes. 



Another point of interest which is raised is the relation between the 

 subdivisions of the Angiosperms — the monocotyledons and dicotyledons 

 respectively. In their Introduction, and again in chapter xv. (Phy- 

 logeny of Angiosperms) the authors discuss the relationship between 



* ' Morphology of Angiosperms.' By J. M. Coulter and C. J. Chamberlain. 8vo, 

 x. and 348 pp., 113 figa. Appleton, New York, 1903. 



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