GEEMAN VERSION. 7 



tions of the Salpce, except those who have been disposed 

 to see somethmg paradoxical in it. Professor Eschricht 

 has recently expressed himself upon it, and is of opinion, 

 that although in appearance it affords an instance of al- 

 ternating generations, yet that the whole may be more 

 readily explained by supposing a double mode of pro- 

 pagation in the solitary individuals ; that is to say, that 

 the Salves in their younger state produce solitary young, 

 and at a later period those of the associated or catenated 

 form, — an opinion to which I have more particularly ad- 

 verted in the proper place. 



In the class of JEntozoa, the Cer caries with their pupce 

 still remained a great enigma, although the opinion which 

 w^as at first entertained of their being equivocal animals 

 was I know wholly rejected; for their relation to the 

 animals " nursing'' them was very far from being under- 

 stood. Sometimes they were considered to be necessary 

 parasites of the " nurses'' who were unable to exist with- 

 out them, as they always contained them and died upon 

 losing them \ again, they were considered as embryos living 

 in a peculiar detached organ, which the " nurses'' were 

 supposed to be, and in consequence received the new 

 name of " germ-sac" (Keimschlauch), being no longer re- 

 garded as independent creatures. With respect to the 

 remaining divisions of this class, I will now only refer to 

 the late views propounded by Professor Eschricht on the 

 cestoid worms, as to their being compound animals {ani- 

 malia corivposita) though not animals organically connected 

 into one whole, or belonging to two generations. The 

 alternation of generations in the Aphides as a superfecun- 

 dation is sufficiently well known. 



So much for the prevailing scientific notions with re- 

 gard to the relations which I have endeavoured to collect 

 under one fundamental idea. 



I beg it maybe observed that I have tried as much as I 

 could to collect scattered fragments into a whole, but that 

 I have always considered this only as the first loose intro- 



