202 PROCEEDINGS OF SOCIETIES. 



canal, but large ovarian tubes ; at one end grows out a small 

 nematoid worm, said to be the male by Sir John Lubbock, who 

 found it. At one period it is the same size as the female, as 

 in Dlplozoon, but the female grows enormously, while the 

 male does not. Schneider, however, says that the supposed 

 large female is merely a huge prolapsed ovarian sack. A 

 third remarkable case is that of Ascaris nigrovenoaa. In the 

 lung of the frog they are found reproducing viviparously. 

 The young so produced pass into the intestine, where they 

 accumulate in the clacaa. They are very minute. When 

 they are set free, and kept in moist earth, they become 

 Anguillulse, and develop into males and females. The eggs 

 laid by these when placed in the frog's mouth pass into the 

 lung, where they develop into the viviparous form again. 

 No male Ascaris nigrovenosa (that is, the lung-infesting stage) 

 has ever been seen, and Leuckart believes the reproduction 

 is asexual. Schneider, however, says he saw spermatozoa in 

 them, and he believes they are hermaphrodite. If this 

 should prove true, the case would be one completely without 

 parallel in the whole animal kingdom. Such an alternation 

 of monoecious and dioecious generations is not known. 



