THE NESTS AND LARV/E OF NECTURUS. 193 



hardly be inferred from the text, my experience shows that the 

 collecting season may be much later than Eycleshymer recorded. 



A noticeable feature of the development as compared with 

 other amphibians that I have studied, is the uniformity in the 

 stage of development of embryos found in different nests in the 

 same locality. On each of the following dates from four to seven 

 nests were secured : June 22, 25, 29, July 5. On each date all the 

 eggs were found so nearly in the same stage of development that 

 only slight differences could be detected in eggs from different 

 nests. This uniformity points to a very short spawning season- 

 perhaps two or three days in this locality; it would seem that 

 all the eggs in a restricted area are laid at nearly the same time. 

 But Eycleshymer ('06) says: "The eggs are first deposited in 

 those localities where the water is shallow and exposed for the 

 greater part of the day to the rays of the sun. The period of 

 egg-laying usually covers two or three weeks. There is no foun- 

 dation whatever for the statement made by Hans Virchow that 

 the animals deposit their eggs so to speak at the same hour." 



I had no success in keeping embryos of Necturus alive in the 

 laboratory, although later in the year larvae of Cryptobranchus 

 thrived under the same conditions. 



2. Nests in a Stream Habitat. I am not aware of any published 

 observations on the nesting of Necturus in streams, hence the 

 following notes on the subject may be of interest. 



During the late summer and early autumn of the past five 

 years, while searching for adults, eggs and larvae of Cryptobran- 

 chus, I have had occasion to overturn numberless stones in the 

 bottom of a large creek tributary to the Allegheny River, in 

 northwestern Pennsylvania. This has resulted in the frequent 

 finding of specimens of Necturus. 



All the specimens found were small, none exceeding 20 cm. 

 (8 in.) in length and most of them were much smaller. The 

 smallest, taken September 13, 1906, was 35 mm. long (see Fig. 6). 

 This specimen was one of a group of six or seven found under the 

 same stone; the others, aided by the swift current, escaped. 



These circumstances led me to suspect that the stream was 

 a spawning ground for Necturus. This suspicion received con- 

 firmation when, on August 24, 1910, I found attached to the 



