AND THE LOWER ANIMALS. 157 



CHAPTER XV. 



NEW EXPLANATION OF EACTS LONG KNOWN. 



It is necessary, before proceeding further, to designate 

 the different phases of the successive multiplication 

 we have been describing, by general terms, analogous 

 to those of larva, nymph, and perfect insect, employed 

 in the description of true metamorphoses. These 

 principal phases are three in number. In the first 

 instance, the egg gave rise to a simple being, an 

 individual having neutral characters ; that is to say, 

 being neither male nor female ; at a later period we 

 observed a compound being, quite as neutral as the 

 first, and each part of which was capable of carrying 

 on an independent existence ; finally, we saw these 

 parts detached, and assuming the organs characteristic 

 of the sexes. M. van Beneden, a Belgian naturalist, 

 to whom we shall have to allude frequently, was the 

 first to distinguish these three stages, and to apply 

 separate names to them.* We shall gladly adopt his 

 nomenclature. 



Thus, we shall apply the term scolex to the ani- 

 malcule which springs from the egg of the Medusa, 

 or of any other species which is reproduced by 

 analogous processes. Giving a more extended sig- 

 nification to the word strobila than that employed by 



* " Recherches sur les Vers cestoldes," 1850. "La Generation 

 altemante et la Digenese," 1854. 



