Feb., 1914.] 
Atypus Milbe7'ti 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 determining the form 
of the plant. The variability especially of the higher plants in 
growth form 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 miles 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.” 
