THE BEGINNINGS OF II FE. 551 



may be very much larger than the rest. For it some- 

 times happens that a mass of the body-substance which 

 would ordinarily divide into three or four germs under- 

 goes organization as a whole, so as to produce a single 

 Tardigrade {b) ^ Such a gigantic specimen is generally 

 remarkable for its superior vigour and for the greater 

 rapidity with v/hich its developmental changes are 

 achieved. In this respect it leaves its more diminutive 

 relatives far behind. Thus it is seen that whilst Tar- 

 digrades may undergo all the processes of heterogenetic 

 Pangenesis which are to be encountered amongst Roti- 

 fers, they also stand, so far as we know, alone, from the 

 fact that they are capable of undergoing this remarkable 

 process of homogenetic Pangenesis, and because, even 

 in the same animal, we may see how imperceptibly 

 heterogenesis may give place to homogenesis -. It is 

 not, however, until we reach other animals, such as 

 Acari and Nematoids, that well attested males and 

 females are, as a rule, encountered. Although even 

 amongst some of them it would seem that buds capable 

 of developing into young Acari or young Nematoids, 

 as the case may be, are still occasionally produced 

 within the reproductive organs of the female quite 

 irrespectively of any male influence. 



^ Loe. cit., p. 442. 



2 Although dead Rotifers do not resolve themselves into masses of 

 matter which are capable of developing directly into similar Rotifers, 

 yet, as Dr. Gros has pointed out, the specimens of Actinophrys or other 

 forms which they do yield by Pangenesis, very frequently develop into 

 Rotifers (though often of a different kind) after a previous existence in 

 one or more inteiTnediate states (see p. 505). 



