Feb., 1914.] AtypiLS Milberti Walck. in Ohio. 251 



the water relation of diverse habitats and diverse plants. The 

 incidental advantages associated with transpiration are 

 undoubtedly these: the water loss reduces the temperature of 

 the plant itself to that of the air about it, thus preventing injury 

 by overheating in direct sunlight; and it aids in the gaseous 

 exchange. The significance of transpiration as one of the forces 

 which bring about the ascent of water in plants cannot be ascer- 

 tained as yet. Data required for the solution of the question are 

 wanting. Other forces must be involved to effect, in humid 

 areas or during periods of defoliation, the lifting of water in the 

 stem to a certain height, and in sufficient quantity. Transpira- 

 tion may be to a certain extent a factor in detennining the form 

 of the plant. The variability especially of the higher plants in 

 growth fonn and in anatomical structure has been shown to be 

 far greater in this respect than hitherto supposed; among all the 

 agencies that affect shape and structure in the plant none has more 

 formative influence than water. But here also critical researches 

 are still required to determine how far differences in the requisite 

 water content of the plant — the water equilibrium of the entire 

 plant — rather than differences in the rate or the amount of tran- 

 spiration are the causal conditions. The examination of these 

 relations must be more quantitative than has heretofore been 

 attempted to be of value to scientific agriculture and to plant 

 geography. 



AN OCCURENCE OF ATYPUS MILBERTI WALCK. 



IN OHIO. 



Carl J. Drake. 



While working on the food of frogs at Cedar Point, Ohio this 

 ■summer I found in the stomach of Rana pipiens Shreber the rare 

 purse-web spider, Atypus milberti Walck. This is the first record 

 of its occurence in the Central States and the second time it has 

 been taken north of Washington, D. C. The frog was caught 

 August 15, about one and one-half iniles southeast of the Lake 

 Laboratory, close to Sandusky Bay. 



Prof. W. M. Barrows recognized the spider as Atypus and sent 

 it to Dr. Banks at the National Museum, who sent the following 

 reply: "This is the Atypus milberti Walck. as you suspect, and 

 far north for it. Last summer Emerton took one half way up the 

 Hudson River. The high cost of living is evidently not affecting 

 frogs, when they take such rare thing as Atypus." 



