114 



IKED A. 



Pairing und Deposition of Eggs. 



The breeding season of RacopJiorus Schlegelii extends from the 

 middle of April to the middle of May, the exact time varying from year 

 to year according to meteorological conditions. It seems most probable 

 that a certain mu albe r of both males and females wake up from their 

 hybernation on every warm day or night during the season, and soon 

 pair on that day or the next. Therefore at such times we often find soli- 

 tary individuals here and there in shallow waters of paddy-fields or ponds, 

 some of these repeating a peculiar cry " kro-Jcro-kro, I ro-kro-kro." 

 This is the sexual call of the males, which keep themselves hidden among 

 grasses or in water and utter these notes elevating their heads a little.* 



The females are always larger than the males. The length in the 

 median line of the former measures about 5 — G cm., while the latter rarely 

 exceed 3 — 4 cm. Once I came on a funny sight of a large female 6 cm. 

 long pairing with a male of 2.5 cm. It seems probable to me that 

 the selection of partners is done mostly during the day time and that 

 towards the evening the female bearing the male on her back retires 

 under ground to prepare for the deposition of eggs. If, however, the 

 temperature should suddenly rise towards evening or during night 

 after some cold days, then partners may be secured during the night, for 

 at such times we often hear the sexual calls at night. After one or more 

 cold da} r s, it is difficult to find any animals either solitary or in pairs, or 

 to find any fresh egg-deposit. 



*This species has another call. In summer it utters ai cry '^kiah-hialt-kiak, kiak-kiak- 

 kiak," and this appears to me to be uttered by both males and females. The time and 

 duration of the breeding season, and the sexual call of this species differ in many points 

 from those of our liana and Bufo. The breeding - season of Rana ton para ria is found in 

 Japan to be a week or fortnight from the end of February to the beginning of March, and 

 the tone of its sexual call is higher and longer than that of Raeophorus. The breeding 

 season of Bufo japonica is in the end of March or the beginning of April and lasts also a. 

 week or fortnight. Its sexual call is louder and higher but shorter. The pairing of Bufo 

 is generally effected on warm nights or days during the season, on land, and then the 

 animals go into water for the deposition of their eggs. The breeding season of liana 

 rugosa is in Japan, iti the middle or the end of June, and goes on also a week or fortnight,, 

 and its sexual call resembles somewhat that of ttaeophorux, but is a little higher in tone. 



