654 A Remarkable Life History and its Meaning. (November, 
parent not of the males alone but of the eggs which they carry 
as well, and therefore of the embryos which these eggs produce. 
Although the chain-salpa gives birth to the solitary form, it is not 
its mother, but simply a nurse. It is not even the father of the 
egg which is fertilized within its body ; although, after it has dis- 
charged its own embryo it may become the father of the embryos 
carried by other chain-salpz. In order to explain this utterly 
anomalous and apparently contradictory manner of development, 
it will be necessary to trace a little more minutely the early 
stages in the formation of the animals which compose the chain. 
It will be well to call attention, in the first place, to the fact that 
no female animal or plant we know of has the power to form 
only a single egg or seed, and it is plain that if there were 
such an organism, it would gradually become extinct, since each 
Ss 
(Fia. 58.) (Fia. 59.) 
Fig. 58. Five Salpæ from a tube, at a very early stage of development. 
Fig. 59. The same, still earlier : 4, the constrictions which mark out the animals ; 
5, ganglia ; 6, digestive organs ; s, ovum. 
generation could be as numerous as the one before it only when 
every embryo survived all accidents and reached maturity. 
The fact that the chain-salpa contains only one egg is in itself 
enough to excite a suspicion that it is not the true female; but 
in answer to this argument it might be said, fairly enough, that 
the whole history of Salpa is a series of anomalies, and that, 
since one more or less would not make much difference, there 13 
no great difficulty in believing that it differs from all other ani- 
mals in producing only one egg. It might be urged that indatt 
nite multiplication is provided for by the power of the solitary 
form to produce large numbers of chains. As we trace "a 
the development of the chain-salpa we soon find much mee 
reasons for doubting that this is the parent of the egg which it 
contains. The sexual products are not usually matured un 
the animal has reached its adult form, and very few animals 
reproduce during their embryonic or larval stages; hut ee 
immediately after the chain-salpa is born, and when it is les 
