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THE AMERICAN NATURALIST [Vol. XL 



Spring, summer, and winter were each regarded as the breed- 

 ing season and, so far as the observations were concerned, with 

 equal degrees of probabiHty. 



Thus there was httle to be gathered from the observations pre- 

 viously made. The only reliable data were to be obtained through 

 a systematic examination of the ovarian eggs at different seasons 

 of the year. Even when this tedious work had been carried out 

 and clews obtained as to the egg-laying period, other and greater 

 difficulties arose. The Great Lakes and their tributary streams 

 in which Necturus had been reported most abundant were usually 

 so clouded by muddy water that search for eggs was futile. Local- 

 ities must be found where the animals were plentiful and where 

 the water remained clear. The small inland lakes of eastern 

 Wisconsin seemed best to fulfil these conditions. Again, no one 

 knew or had even suggested where the animals deposited their 

 eggs, whether in deep or shallow water, whether they were laid 

 in masses in open places like those of Ambly stoma, or scattered 

 in strings like those of the toad, or laid singly and concealed among 

 the leaves and branches of aquatic plants like those of the newt. 



The knowledge of the egg-laying habits of other Amphibia 

 gave no clue, but nevertheless the work was continued and after 

 years of persistent and patient effort Professor Whitman finally 

 discovered the nests and eggs of Necturus. Only those who have 

 for years been baffled in their attempts to obtain the embryological 

 material of other North American Urodeles, such as the Siren, 

 Amphiuma, and Cryptobranchus can properly appreciate the 

 enormity of the task. 



Through the kindness of Professor Whitman the writer first 

 obtained a knowledge of the haljits and breeding places of Nec- 

 turus, and each sinnmer for the past eight years has made obser- 

 vations on the habits of these animals in their natural environment. 



Egrj4ayin(j. — The time of egg-laying varies in different lakes, 

 depending upon the time when tlie temperature of the water reaches 

 a certain <l(><;Tr(\ In ttn- hirircr. dct'iHT lakes with bold shores 

 this is much hit.-r than in th..s(> [x.^sexsi,,- wid(> shoals. Again, 

 in the individual hikes the time is dependent upon the same con- 

 ditions. The eggs are first deposited in those localities where 

 the water is shallow and exposed for the greater part of the day 



