General Account of the Ithacan Anura. 7 



addition of chloral hydrate to the water. In this way, permanent 

 preparations may be made. Furthermore, males of the Ranidse and 

 of the genus Bufo have continued in the embrace for several days after 

 a female has died. Occasionally they seize a dead female and main- 

 tain the clasp for varying periods. 



In the numerous laboratory-mated pairs, which proved unfruitful 

 as a rule, the males often continued the embrace for long periods. On 

 several occasions the females died or else showed ugly scars on their 

 breasts from the long hold of the males (Plate iv, Fig. 3). In one 

 instance, a pair of Rana pipiens so remained continuously for five weeks 

 and doubtless would have continued longer had the aquarium water- 

 supply been watched more carefully; the male, in this instance, died at 

 the end of the period named. Several other periods closely approach- 

 ing this have been noted for other species. In all the mated pairs 

 captured afield, the males normally retained their holds, no matter 

 how long the journey to the laboratory, however roughly handled, or 

 however hot the glass jar became from sun exposure. If they broke 

 on the trip, they soon resumed, and seldom released when transferred 

 from aquaria to aquaria or to photographic stands. 



This amorous disposition frequently persists with unpaired males 

 long after the active pairing season in nature is over, occasionally for 

 as long as one month. In one instance an emaciated male Chorophilus 

 triseriatus mated two and a half months after its customary breeding 

 season. Then, too, unmated or fresh males may often seize a spent 

 female and retain her for considerable periods, sometimes until her 

 death. 



Even with males which have once mated, records have been noted 

 where mated pairs continued in the embrace or else resumed the em- 

 brace after the eggs were laid. In six species, this has been observed; 

 the exceptions are Rana catesbeiana and Rana clamata, in which it 

 doubtless has been overlooked because of the difficulties of observation 

 and of their solitary nature. In the tree-toad the male has continued 

 in the embrace after ovulation; in the peeper, 2 days afterwards; wood- 

 frog, 3 days; meadow-frog, 4 days; pickerel-frog, 7 days; and toad, 12 

 days. This phenomenon is more likely to be observed in laboratory- 

 mated pairs or field-mated pairs confined in the laboratory. It is 

 suggestive of the possibihty of a male mating more than once. 



The males of the genus Rana usually have the thumb much enlarged 

 at the breeding season and the margins of the webs of the hind feet are 

 different from those of the females. In some they may be convex 

 (Plate III, Fig. la) instead of concave, or less concave than in the female. 

 Almost invariably, the male of a mated pair of Rana proves smaller 

 in size (Plate ii, Figs. 2-4) and darker in color. The latter fact may 

 be partially due to the male's great activity in searching for the more 



