AND THE LOWER ANIMALS. 175 



Hera, then, there is a second generation of scolex — a 

 deiito-scolex — which multiplies under its new form of 

 campanularia. The resulting polypidom is in some 

 measure a compound deuto- scolex, which develops a 

 strobila, represented by the capsule containing the 

 reproductive bodies. Finally, the latter, plus the ova 

 in their interior, are the proglottides, and correspond 

 to the small medusoids which are transformed into 

 Aureliee, or even to Aureliae themselves. There 

 is this distinction, however, between the two: the 

 reproductive bodies of Campanularia are fixed to the 

 polypidom, whilst those of Aurelia are free and 

 floating, and lead an independent existence. 



The analogies we have attempted to establish may 

 appear questionable to those who are unacquainted 

 with the whole of the facts ; but a perusal of the 

 works of Ehrenberg, * Krohn, Kolliker, Daly ell, 

 Dujardin,f and Derbes^ will leave hardly any room 

 for doubt. By studying Van Beneden's splendid 

 memoirs on Campanularia and Tubularia J — not- 

 withstanding the errors in determination which the 

 author has since corrected — it will be seen that 

 facts which are apparently devoid of analogy are 

 associated undeniably by a host of intermediate 

 ones. 



It is very necessary, in a study of this sort, to 

 point out, in the commencement, the circum- 



* " Corallenthiere des rothen Meeres," 1834. 



f " Memoire sur le Developpement des Meduses et des Polypes 

 Hydraires." — Annales des Sciences naturelles, 1845. The chief 

 results of this admirable memoir have been detailed in my 

 " Eambles of a Naturalist." 



% " Memoires de l'Academie de Bruxellcs," 1843 and 1844. 



