III.] 



THE COMMON FROG. 



skin of the belly of the Siluroid fish, Aspjrdo 

 hatj'achics. Here he found that "the whole lower 

 surface of the belly, thorax, throat, and even a por- 

 tion of the pectoral fins, showed numerous shallow, 

 round impressions, to which a part of the ova still 

 adhered." He concludes that " it is more than 

 probable that towards the spawning time the skin 

 of the lower parts becomes spongy, and that, after 

 having deposited the eggs, the female attaches them 

 to it by merely lying over them." " When the eggs 

 are hatched the excrescences disappear, and the skin 

 of the belly becomes smooth as before." Even in the 

 highest class of animals {Mammalia) we are familiar. 



Daciylethra caj>ejisis. 



in the Kangaroo and Opossum order {Marsiipialia), 

 with a special external receptacle (the marsupial pouch) 

 for the protection and secure development of the 



