The Leopard-frog or Meadow-frog, Rana pipiens (Schreber) . 55 



or duration of the male's embrace. On April 25, 191 1, 1 found a live male 

 embracing a dead female which must have died several days previous. 

 Did she die in the embrace? Two days later, when I returned, the pair 

 was in the same spot. 



The normal embrace is pectoral (Plates n, Fig. 4; iv, Fig. 4). The 

 males while amplexating often half inflate the vocal sacs for short or long 

 periods (75 times in one male) before croaking. These inflations may 

 be rapid, as many as 60 per minute being noted. Sometimes for short 

 periods a male will embrace another male. Once we recorded a male 

 which in captivity resumed the embrace after its mate had laid its egg- 

 complement. On April 1 they were captured ; two days later the female 

 laid ; thereafter, for varying periods, the male broke and resumed em- 

 braces until April 5. More curious still, at 1 p. m., May 3, 1907, a male 

 Rana pipiens was found embracing a female with a perfect lumbar 

 amplexation. He kept it for 3 hours. He was handled roughly with- 

 out making him relax his hold. Later, upon transference to the photo- 

 graphic stand, he broke his hold. 



Cross-embraces with other species are not unusual in captivity. 

 The matings with other species are : males of Rana pipiens with females 

 of Rana clamata, Rana palustris, Rana sylvatica, and Bufo lentiginosus 

 americanus. In this last instance, on May 6, 1907, a male embraced a 

 female Bufo with a typical amplexation, i. e., pectoral with hands 

 appressed to the breast, and continued thus one day. In this species 

 we have recorded two cross-embraces in the field. On April 28, 1911, 

 we found toads and meadow-frogs mating in a certain area, and one pair 

 proved to be a male meadow-frog mated with a toad. On the same day, 

 in another area, pickerel-frogs and meadow-frogs were mating and laying 

 in great numbers, the two species sometimes using the same twigs. 

 It seemed probable that there should be cross-embraces. Later in the 

 day, at this same place, there was found a male Rana, pipiens mated 

 with a female Rana palustris (Plate iv, Fig. 2). All hopes of fertile eggs 

 vanished, however, because the female waited four or five days before lay- 

 ing her eggs, which were spoiled before ovulation. Another interesting 

 incident happened in one of the aquaria several years ago, when 

 males of this species were put with some bowfins (Amiatus) ; at several 

 different times, a male embraced an Amiatus and rode around on its 

 back for some time. 



THE OVULATION. 



Leopard-frogs prefer cat-tail swamps, marshy expanses of other types, 

 grassy overflows, and shallow dead streams. In other situations than 

 these, they breed sparingly. In austral localities they may begin ovula- 

 tion before April 1. At Ithaca the ovulation rarely precedes April 10. 

 The records from 3907 to 1912 are shown in the table on page 56. 



