1905] CURRENT LITERATURE 387 
of “intracellular pangenesis.” Modifications of the germinal organization are 
probably the immediate causes of evolution. Even a slight alteration in the 
unsegmented egg may result in a profound change in the adult as illustrated in 
the production of dextral and sinistral forms of mollusks by maturation taking 
place, now at the one pole, now at the other. 
Dwicut?e concludes that evidences from human anatomy offer no support 
for the theory of evolution by minute changes, and that although they do not give 
any direct support to the mutation theory they are not in disaccord with it. 
Bamtey?" discusses the relation between taxonomy and evolution, pointing 
out some of the weak points in the present system of classification, particularly 
in that taxonomic systems are rigid and arbitrary, whereas the organic world is 
plastic and changing. He holds that the ideal taxonomy of the future must make 
no distinction between “natural” and “artificial” forms, and that the type of 
a species should be the real phylogenetic or biological type instead of the 
first specimen which chanced to be named. There can never be such a thing. 
a8 a satisfactory ‘‘stable’’ nomenclature. 
WHEELER”? considers the mutation theory even more important in the explan- 
ation of the origin of new instincts, new functions and new habits of life, than 
for the origin of new morphological characters, especial mention being made of 
Sag species and species with profound and sudden metamorphoses.—G. H. 
HULL, 
THE GERMINATION of Coleochaete scutata has been studied by ALLEN’S who 
pe paid particular attention to cytological features of the first and second divi- 
_ of the fertilized egg. Fertilization takes place in the summer. After resting 
ont the winter, the fertilized egg segments into a number of cells, in each of 
which a zoospore is developed. 
In the prophase of the first mitosis a condition is 
Tegards as a genuine synapsis, during which a fusion 0 
— as in his account of Lilium. The chromosomes formed 
me bivalent, the line of separation corresponding to the earlier 
‘pitting of the spirem. Occasionally the arrangement of chromatin granules 
suggests that the chromosomes may be quadrivalent. The number of chromo- 
“mes is probably thirty-two. No centrosomes or centrospheres could be dis- 
tinguished. At the second division the chromosomes are longer and more ere 
= ince of the first division. A cell plate is formed at each ae eae 
spond quite closely with the heterotypi¢ and homotypic divisions 
found which the author 
f somatic chromosomes 
from the spirem 
longitudinal 
*° Dwicet, THOomMas, Mutations. Science N. S. 21:529-53?- 1995: 
~ pes 1. H., Systematic work and evolution. Science N. S. 21:532-535- 
i » ai; 
* WHEELER, W. M., Ethology and the mutation theory. Science N. S. 2 
535-$40. 1905. 
* Alten, C. E., Die Keimung der Zygote bei Coleochaete. 
Ber. Deutsch. Bot. 
G 
esells, 23: 285-292. pl. 13. 1905. 
