1908] CURRENT LITERATURE 395 
the resting stages of the mother cell is composed of a number-of knots connected 
by filaments. The pairing of the reticulum appears at a very early stage. The 
number of pairs of knots, though it is impossible to make an accurate count, far 
exceeds the number of pairs of chromosomes. She concludes that in Funkia it 
is inadvisable to call the knots prochromosomes. (2) Occasional contact between 
the pairs of knots is observed in synapsis, but they do not constitute clear cases 
of fusion. (3) The double thread is formed from the reticulum during synapsis 
, due to the paired arrangement of the constituents of the nucleus. (4) The double 
thread fuses into a single spirem, but at the time of segmentation into chromo- 
somes it splits along the line of fusion (thus an element of each bivalent chromo- 
some is not one-half resulting from the division of a single spirem, but an entire 
Piece of the double thread which fused to form a single spirem). (5) Heterotypic 
division of chromosomes takes place along this fission, so that there is a true 
reduction division. (6) In each of the daughter chromosomes a new second split 
occurs longitudinally. (7) The reticulum and knots in the nucleus of the pollen 
grain are unpaired throughout, but a double structure is found in the prophase 
of the somatic nucleus. (8) The number of chromosomes in the somatic nucleus 
of Funkia ovata and F. sieboldiana seems to vary from 36 to 48, probably is 48, 
the reduced number being near 24.—S. YAMANOUCHI. 
__ Fossil Osmundaceae.—KipsTon and GwyNNE-VAUGHAN have recently pub- 
lished a second contributions on the extinct Osmundaceae, which deals anatomi- 
cally with two species of a new genus (Zalesskya) from the Permian of the Ural. 
Z. gracilis and Z. diploxylon are characterized by a central cylinder, which the 
authors infer to be protostelic from the manner of exit of the leaf traces. Unfor- 
tunately in one species the center of the fibrovascular tissues of the stem has dis- 
‘appeared through maceration, correlated with fossilization, and in the other by 
the crumbling away of the stony matrix. The authors admit that the general 
anatomy of the fossils is not distinctively osmundaceous. They place great 
ostic importance in this connection, however, on the minute structure of 
the xylem tracheids, which are characterized by multiseriate pits and vessel-like 
Perforations of the pit membranes of the terminal walls. The authors seem to 
attach a somewhat exaggerated importance to these features, however, since both 
save long been known to occur in ferns not related to the Osmundaceae. They 
infer that their fossils make it “clear that the central ground tassue of the recent 
Osmundaceae must be regarded as phylogenetically derived by modification from 
the central xylem of a solid (sic) protostele and that primitively it had no sooo 
=~ the cortex. whatever.’ This statement appears to have scarcely a better 
in logic or fact than their contention in the first article that foliar gaps 
sea Primitively absent in the Osmundaceae. Even if it be admitted that the 
Authors’ Species are osmundaceous, which is very far from being rotten 
Siclusion reached appears hardly in accordance with sound reasoning. 
's Kipston, R., AND GWyNNE-VauGHAN, D. T., On the fossil Osmundaceae. 
I, 
Trans, Roy. Soc, Edinburgh 462: 213-232: pls. 1-4. 1908. 
