November 11, 1898.] 



SCIENCE. 



653 



of the membrane the granules gradually 

 disappear and apparently either unite di- 

 rectly to form the membrane or are absorbed 

 through its growth. Some preparations 

 give evidence that the granules fuse to- 

 gether to form the membrane, and the 

 writer is inclined to this interpretation of 

 the phenomena presented. 



The further stages in the elongation of 

 the membrane into the cilia-bearing band 

 of the antherozoid have been described by 

 the writer in another place. 



The Blepharoplast in the Spermatogenesis of 



Marsilia. De. W. E. Shaw. 



In the development of the male prothallia 

 of Marsilia vestita no blepharoplasts or other 

 centrosome-like bodies are found in any of 

 the six cell divisions or resting stages pre- 

 ceding the formation of the primordial 

 spermatogenous cell, 'central cell,' of each 

 of the two antheridia ; nor are any such 

 bodies found in that cell or during its divi- 

 sion. The first appearance of centrosome- 

 like bodies is in the spindle poles during the 

 telephase of the second division of the sper- 

 matogenous tissue. After this division is 

 complete, i. e. , in the ' grandmother cells ' 

 of the spermatids, each of these bodies 

 grows into a pair of blepharoplastoids which 

 increase in size. They remain together and 

 move into the other region of the cytoplasm, 

 and disappear during the following cell 

 division. During the anaphase or telephase 

 of this division there are formed, at the 

 poles of the spindle, new bodies. After the 

 division, i. e., in the ' mother cells ' of the 

 spermatids, each of these bodies develops 

 into a pair of blepharoplasts. The blepharo- 

 plasts separate, at the same time increasing 

 in size, and move to opposite poles of the 

 cell, where they remain throughout the last 

 division leading to the formation of the 

 spermatids. The further development closely 

 resembles that of the blepharoplasts in the 

 spermatozoids of the cycads. 



Observations on the Relative Moisture Content 



of Fruit Trees in Winter and in Summer. 



Professok C. S. Crandall. 



From samples of trunks and branches of 

 apple trees taken January 15th and 16th 

 and August 3d, and thoroughly air-dried, 

 with careful weighing before and after, the 

 author concludes that, as grown under 

 Colorado conditions at least, there is hardly 

 an appreciable difference between the sum- 

 mer and winter moisture. 



In the discussion which followed. Pro- 

 fessor D. T. MacDougal stated that the 

 water content in the trees in August was 

 practically the winter content, the separa- 

 tive layer in the leaves having probably 

 already begun to form, and that for . the 

 determination of the summer moisture sam- 

 ples should have been taken sixty to sev- 

 enty days earlier. 



Some Observations bearing upon the Symbiotic 

 Myeoplasm Theory of Grain Rust. Pro- 

 fessor H. L. BOLLEY. 



Many facts and arguments go to show 

 that Erickson's hypothesis has not been es- 

 tablished, and is not necessary to account 

 for the first appearances of grain rust. The 

 author finds that uredo and Eecidiospores 

 {A ec. berberidis, U. rubigo-vera and U. graminis) 

 germinate readily when placed under fa- 

 vorable conditions ; that, when other condi- 

 tions are the same, shaded, spindling plants 

 are as much subject to infection as those 

 grown in the sunshine, and, finally, that 

 when oats and wheat were grown in rust- 

 proof cages there were no infections what- 

 ever, although close outside and for miles 

 around every plant bore numerous pustules. 



Some Unique Examples of Dispersion of Seeds 

 and Fruits. Professor W. J. Beal. 

 A popular account, illustrated by speci- 

 mens. To be printed in full in The Ameri- 

 can Naturalist. 



Starch Distribution as affected by fungi. De. 

 Byron D. Halsted. 



