ARTIFICIAL PARTHENOGENESIS IN FROGS 2th 
starfish and some annelids by gentle agitation, in the egg of 
the frog it can be done by puncturing the surface layer. 
Future experiments will decide whether or not the leucocytes 
play the réle of the second factor which Bataillon ascribes to 
them. 
Loeb and Bancroft tried to ascertain the sex of the par- 
thenogenetic frog and tadpole which they obtained. The 
Fig. 76 
ay ay 76 and 77.—Parthenogenetic frog and parthenogenetic tadpole (nat- 
gonads contained eggs in both cases. This at first sight might 
be taken to indicate that both were females, but the problem is 
complicated by the fact found by Pfliiger, and recently worked 
cut by Kuschakewitsch,! that very often in the early stages the 
gonads of a frog may contain eggs which afterward degenerate. 
Such “‘intermediates”’ may develop into males. 
The gonads of the parthenogenetic frog obtained by Loeb 
and Bancroft agreed with Kuschakewitsch’s description of 
an “intermediate”? which is in the process of developing into a 
male. 
1 Kuschakewitsch, Festschrift f. Richard Hertwig, Bd. II, p. 145, 1910. 
