588 



H. S. 'Jennings 



in the progeny ? Similar questions must be asked for each of 

 the organs of locomotion and other structures, seen in Fig. 2. 

 These questions regarding details show that we do not after 

 all gain much for understanding inheritance in Protozoa by such 

 statements as that "parent and progeny are the same and so must 

 be alike." For in simple transverse fission of Paramecium there 

 is no reason that is at once apparent, why the anterior product 

 should have at its posterior end a point, as its parent had, nor why 

 the posterior product should have a blunt anterior end with a 



Fig. 2 Oxytricha fallax. Mere transverse fission would leave the five large setae 5 with only one of 

 the resulting individuals. , , 



groove'along one side; these are not simply passed on,'ready made, 

 to the progeny. Again, the simple transverse fission of Oxytricha 

 does not account in the least for the fact that the anterior product 

 of division has the row of five setae at its posterior end. The five 

 setae might be transmitted directly to the posterior daughter-infus- 

 orian, but the anterior individual would naturally be left quite 

 without such structures. Indeed, by repeated mere divisions 



