92 ESSAY ON CLASSIFICATION 



would transform them into individuals similar to their parents; ^-^ 

 and they show further, that this brood originating from eggs may 

 increase and multiply by producing new individuals like themselves 

 (Syncoryne), or of two kinds (Campaniilaria), or even individuals of 

 various kinds, differing all to a remarkable extent, one from the 

 other (Hydractinia), but in neither case resembling their common 

 parent. None of these new individuals have distinct reproductive 

 organs, any more than the first individuals born from eggs, their 

 multiplication taking place chiefly by the process of budding; but 

 as these buds remain generally connected with the first individual 

 born from an egg, they form compound communities, similar to 

 some polypstocks. Now some of these buds produce at certain seasons 

 new buds of an entirely different kind, which generally drop off from 

 the parent stock at an early period of their development (as in 

 Syncoryne, Campanularia, etc.), and then undergo a succession of 

 changes which end by their assuming the character of the previous 

 egg-laying individuals, organs of reproduction of the two sexes de- 

 veloping meanwhile in them, which, when mature, lead to the pro- 

 duction of new eggs; in others (as in Hydractinia) the buds of this 

 kind do not drop off, but fade away upon the parent stock after 

 having undergone all their transformations and also produced, in 

 due time, a number of eggs.^-^ 



In the case of the Medusae proper the parent lays eggs, from which 

 originate polyplike individuals; but here these individuals divide 

 by transverse constrictions into a number of disks, every one of ^vhich 

 undergoes a succession of changes which end in the production of as 

 many individuals, each identical with the parent, and capable in 

 its turn of laying eggs (some, however, being males and others fe- 

 males). But the polyplike individuals born from eggs may also multi- 

 ply by budding and each bud undergo the same changes as the first, 

 the base of which does not die, but is also capable of growing up 

 again and of repeating the same process. 



"" Polymorphism among individuals of the same species is not limited to Acalephs; 

 it is also observed among genuine Polyps, the Madrepores, for example, and among 

 Bryozoa, Ascidians, Worms, Crustacea (Lupea), and even among Insects (Bees). 



^' I have observed many other combinations of a similar character among the Hy- 

 droid Medusae, which I shall describe at full length in my second volume and to which 

 I do not allude here, as they could not be understood without numerous drawings. The 

 case of Hydractinia is not quite correctly represented in the works in which that ani- 

 mal has been described. [See Agassiz, Contributions, IV (1862), 181-372.] 



