100 METAMORPHOSES OF MAN 



jagged orifice. It is in this prison that the young 

 balsenus, hitherto free and unrestrained, is confined 

 for the rest of its days. It is folded in two; and its 

 feet, henceforth useless as fins, are transformed into 

 recurved and beautifully ciliated cirrhi. It is these 

 latter which, when moved by powerful muscles, hence- 

 forth provide our little monk with food. They form 

 a sort of double plume above the head, projecting 

 beyond the opening of the valves, and when rapidly 

 moved backwards and forwards, they draw to its 

 mouth the food which the balaenus cannot now go in 

 pursuit of. 



The modifications which metamorphosis brings 

 about, extend beyond mere form and structure. 

 Very important functional changes are also effected 

 by it. It is only when the balsenus is thus impri- 

 soned and deformed, when it is blind and can no 

 longer move from place to place, that its reproductive 

 organs are developed. Here is an instance of an 

 animal which when in its nymph and larval state is, 

 as regards the possession of the essential characters 

 of an animal, a higher being than when it assumes 

 the adult form ; but in neither of the former condi- 

 tions can it be a parent. The progress of develop- 

 ment has degraded it in the animal scale ; but whilst 

 this progress has made all the functions but one sub- 

 ordinate to that of nutrition, it has been the means 

 of producing the apparatus which insures the con- 

 tinuance of the species. 



The result of recurrent development seems in many 

 cases to be the sacrifice of all other functions to that 

 of reproduction. This final object is even still more 

 apparent in the lower Crustacea, and especially among 



