44 ALTERNATE GENERATION 



veloped, than one which is fixed or not free in its move- 

 ments, so we are certainly justified in considering, that 

 the sohtary Salpa are superior in their development to 

 the associated ; and this is even admitted by Eschricht, 

 when he allows, that though late, eventually the associated 

 is changed into the solitary form. But, in the second 

 place, this expression implies that an animal in its younger 

 and less developed condition, produces young more highly 

 developed than those produced by it when it is itself 

 older and has reached a higher stage of development; and 

 if the difierent generations or forms of the progeny are 

 now compared, not with each other, but both generations 

 with the parent animal, the above hypothesis will be 

 found also to imply, thirdly, that a young animal produces 

 a progeny of a form and organization which is attained 

 by itself, only at a later period, and that when it has 

 attained its full development, it should only be able to 

 produce young far inferior to itself, and which by pro- 

 gressive transformation alone, afterwards attain to the 

 degree of development of the former generation and of 

 the parent.* But the worst conclusion to which this 



* In meeting the objection, which he himself has made to his own theory. 

 Professor Eschricht declares : " that it is certainly extraordinary that the foetus 

 while still within the mother, should present a form at which the mother itself 

 does not arrive till aßerwards ; hut the wonder will in a great measure be re- 

 moved, when it is remembered that the difference of form (described ia Sect. 15,) 

 depends on the relatiom which the animal assumes in its connexion with the 

 others, and not on necessary gradations in the progress of its growth towards 

 completion, and it consequently possesses no analogy at all with what is termed 

 metamorphosis." (At Pormsforskjelligheden beroer paa Forholdene i Kjoede- 

 dannelsen, ikke paa uodrendige Gradationer i Uddamielsen, altsaa aldeles ikke 

 ere analoge med de saakaldte metamorphoser. I have here assumed the 

 words " ere analoge" to be an error of the press, and "Eormsforskjelligheden" 

 to be the subject of the proposition. But nevertheless the sense of the 

 passage is stul obscure. — Germ. Trans.) Probably there is here some error 

 of the press or of expression, which prevents a clear apprehension of the 

 author's meaning. I willingly grant him, however, in the meanwliile, that 

 in one respect no metamorphosis does occur ; for I am convinced that the 

 associated salpce never become other than associated, and are never sohtary. 

 But on the other hand, it appears to me that Professor Eschricht, who 

 mairitaias that the associated salpce assume in process of time, though late, 

 the solitary form, wül find it difficult to show that such a transformation is 

 brought about in any other way than by a sudden transition, that is by a 

 metamorphosis, from the circumstance that the associated salpce retain for so 



