ORDER BATRACHIA. 437 



sion of the frosts, they are sometimes thus employed in the 

 recesses of the waters. The season of love is announced in 

 the males by the presence of a black papillose wart, which 

 grows on the fore-feet. At the same time their belly swells ; 

 on opening it there is found in that of the male a mass of 

 white jelly, and some black grains enveloped in a mucosity 

 in that of the female. 



If love be early in its diagnostics among these reptiles, it 

 is slow in its effects. The intercourse lasts for many days, 

 sometimes even fifteen or twenty, Bartholin has observed 

 it not to finish until the fortieth day. The feet of the male 

 become considerably enlarged, growing stiff and curved, so 

 that he cannot separate himself from the female. Under such 

 circumstances the head of the male has been cut off without 

 his ceasing to fulfil his destination, namely, that of fecun- 

 dating the eggs. But if the tubercles of the thumbs be 

 removed, he can no longer maintain his position. 



This intercourse, which takes place but once a year, is 

 followed by the exclusion of the eggs from the body of the 

 female. At the moment of this exclusion, they are bedewed 

 with the fecundating fluid of the male. Some hours after the 

 operation is terminated, the male separates from the female, 

 and at the end of one or two days his feet recover their usual 

 flexibility. 



The eggs of frogs are always abandoned in the water, where 

 they float at the surface, while those of the majority of the 

 toads are deposited in the mud. They are connected with 

 each other in the form of chaplets. 



Repeated observations on the mode of generation in the 

 frogs, clearly prove that it is not performed in the same way 

 as that of the preceding classes of animals, but in a mode 

 analogous to that of fishes. There is also not the least truth 

 in the assertion of Mentzius, a professor of Leipsic, that the 



