100 



But, aside from the interest attached to this new genus of the Volrociniae from 

 the botanical point of view, it may be found to have important relations to odors 

 and tastes in water supplies, when it will become the enemy of engineers and 

 water commissioners, as other members of this group have done l)efore. For ex- 

 ample, Volvox ylobator has caused much trouble in Rochester, X. Y., r>y imi)arting 

 a disagreeable fishy odor to tlie city water supply, and in Massachusetts Pandorina 

 and Eudorina have caused similar troubles on a smaller scale. Fl-odorina, com- 

 ing as it does between Volvox and Eudorina in the classification, may be looked 

 upon with suspicion in this respect, if it ever infects a water supply in a sufficient 

 quantity. On account of the filthy condition of the canal water in which it was 

 found in Lafayette, and the number of other forms growing with it. no idea could 

 be formed as to the nature of the otlor, if any, of Pleodorina. 



Forms of Xanthium Canadense and X. strumarium. Bv J. C. Arthur. 

 In the absence of the author the outline of the pnper was pi-esented l)v Mr. 

 Wm. Stuart and photographs of the two species were shown. The si)ecies in their 

 most typical forms diflier widely in the outline of the leaf and character and size 

 of the burs. X. Canadense has a flowing sul)-entire outline to the leaf, and large, 

 strongly hispid fruit covered thickly with prickles, while A', strumarium has den- 

 tate leaves and smaller glabrous fruit with fewer prickles. All gradations exist 

 between the two types, due possibly to hybridization. 



Notes on Wood Shuinkaue. Bv M. J. (toijikn. 

 The increase or diminution in size of a piece of wood, due to its possession of 

 a greater or le-s amount of moisture, is well known, as is also tiie fact that tiiis 

 change in size may be accompanied by the exjienditurc of a great deal of force. 

 If an unseasoned piece of wood has two sides fastened rigidly so that it can not 

 shrink across the grain, and then be exjiosed to a current of comparatively dry 

 air, it will very soon break, the break being in the direction of the length of the 

 cells of which the wood fibers are composed; or if a piece of dry wood be con- 

 fined rigidly to [)revent any increase in size and then be satiii-atcd with moisture, 

 it will tend to swell and the force will he sufficient to crush the til>er> where they 

 are in contact with whatever confines them. 



