72 



The Green-frog, Rana clamata Daudin. 



or other males are afterwards frequently found for varying periods. 

 In fact, many have been captured in this way. The pectoral type of 

 embrace (Plate xvii, Fig. 1), common to the genus, obtains. This am- 

 plexation, on May 22, 1906, appeared to be of the Hyla type (Plate iv, 

 Fig. 6). Such an embrace might occur again with a small male, or if 

 the species mate before the regular breeding period. In the above 

 instance, however, the embrace was broken, and the next time the 

 male mated in the manner of Rana. The males of this solitary species 

 are less given to seizing females of other species than the other forms 

 of Rana (bullfrog excluded) . Cross-embraces between green-frog males 

 and females of Rana pipiens, palustris, and sylvatica have been recorded. 

 Males at the height of their breeding season will embrace each other 

 for short periods. 



THE OVULATION. 



The green-frog begins ovulation in late spring or early summer. 

 Our first records are : 



It appears, then, that air-maxima for the day of the record range 

 from 65 to 83 degrees or average 74 degrees; for the day before the 

 record they range from 64 to 89 degrees or average 76 degrees. No 

 record is flanked on either side by a temperature less than 64 degrees. 

 An average date of first egg-laying would be June 2, or June 7 if we 

 consider the 1911 record abnormal. May 1911 was remarkably warm, 

 the average being nearly 65 degrees, which was higher than that for any 

 other May since 1880, and only one degree below the June normal; 

 hence the record of May 12, almost a month earlier than the average 

 date. The eggs first became common on the following dates: 



