THE BEGINNINGS OF LIFE. 525 



in its turn, becomes transformed into an embryo, which 

 immediately develops into one of the Tardigrades. 



These facts concerning the transformations of the 

 specimens of Actinophrys derived from Rotifers, may 

 be paralleled by others which are generally in accord- 

 ance with what we have hitherto been led to expect 

 by the history of previous metamorphoses. In the first 

 place, specimens of Actinophrys derived from quite a 

 different source are also, according to Dr. Gros, capable 

 of undergoing similar developments. Thus, some spe- 

 cimens directly derived from Euglense may, as we have 

 already mentioned, be directly converted into Rotifers ■ 

 whilst others, apparently similar, may be converted 

 either into Tardigrades or into Nematoids\ And, 

 secondly, these statements are borne out by others, 

 based upon evidence of the most unmistakeable character, 

 to the effect that Nematoids, Tardigrades, and the 

 largest Rotifers may each of them be directly produced 

 by the heterogenetic transformation of similar vegetal 

 vesicles^. Dr. Gros says he has seen thousands of large 

 rose-coloured Euglen^ gradually decolourize and become 

 converted into encysted animal embryos, some of which 

 produced large Rotifers, others Tardigrades, and others 

 Nematoids. And the latter, though sexless at first, sub- 

 sequently grew into well-developed males and females. 



^ Loc. cit., pp. 300, 309. 



2 In this respect, therefore, they are like all the inferior members of 

 the series — they may either be the final outcome of a series of ascending 

 developments, or they may be the products of a direct metamorphosis. 



