Igto] CURRENT LITERATURE 65 
and O. grandiflora, as well as certain differences in interpretation, which will be 
pointed out. 
The present account substantiates the earlier one in two fundamental points: 
(1) in synapsis the nuclear reticulum contracts into a ball, during which a more 
or less continuous thread is formed, byt there is no evidence of a pairing of 
separate threads; (2) the thick spirem finally segments in such a way as to show 
that the chromosomes must have been arranged in a single series end-to-end. 
These are the two essentials of the method of heterotypic chromosome formation 
according to the account of FARMER and Moore, Mortier, and others. 
The author of the paper under review was formerly a strong advocate of the 
method of reduction by a lateral pairing of spirems previous to synapsis. This 
fact, together with the fact that he is the third investigator who has now given 
the same account as regards the essential points of chromosome reduction in 
Oenothera, places practically beyond question the presence of a telosynapsis 
(end-to-end pairing) instead of a parasynapsis (side-by-side pairing) in this genus. 
In the nature of things, a lateral pairing of delicate threads previous to synapsis 
is more difficult to demonstrate than the cross-segmentation of a thick spirem 
after synapsis (see GATES 08, jigs. 22-26). But RosENBERG has reiterated his 
belief in a parasynapsis in Drosera, and has recently't brought forward some 
particularly clear evidence of a lateral pairing in that genus. A number of other 
investigators have given more or less convincing evidence of a parasynapsis in 
other forms. In the light of these facts it seems pretty evident that both these 
general methods of reduction occur in plants, a view which I have advanced in 
former papers. When cytologists become ready to admit that the evident differ- 
ences in accounts of reduction are not all differences of interpretation, but are 
mm many cases differences in fact, we shall have taken a forward step in the science 
and shall be ready to attack the problem of the meaning of the differences in 
chromatin behavior involved. To admit that all differences in accounts are due 
to real differences in chromatin behavior, would introduce laxity into interpre- 
tations which must necessarily always be critical, but nevertheless it must be 
admitted that in some of the more recent papers, clear and important differences 
in the method of the chromatin behavior have been established. 
Several differences between Davis’s account of reduction in O. grandiflora 
and my account of that process in the O. Lamarckiana forms may now be pointed 
out. They are partly differences of interpretation and partly differences of fact. 
Davis states that the chromatic bodies in the resting nuclei are probably pro- 
chromosomes, but this is evidently the statement of a pious wish rather than an 
observation of fact, for he himself finds variation in the size and number of such 
bodies. He has unfortunately failed to distinguish between the true synapsis 
°F synizesis, which is familiar to all cytologists as the stage in which the thin 
and delicate spirem is contracted into a ball, and the second contraction phase, 
_ "' Rosenserc, O., Cytologische und morphologische studien iiber Drosera longi- 
jolia rotundifolia, Kungl. Svenska Vetenskapsakad. Handl. 43:1-64. pls. I-4. 1909. 
