Van Beneden on the genera Eleutheria and Synhydra. 245 



be classed among the TubulariadcB^. This subject seems to be 

 of sufficient importance for us to recur to it ; for the opinion which 

 we then advanced has been confirmed by subsequent researches. 



The first idea of M. de Quatrefages^ at the sight of the beings 

 which he has called Eleutheria, was, that they were in the state 

 of larvse ; but on detecting eggs in the majority of them he had 

 no longer any doubt as to the perfect state of the new polyp ; 

 since it is only in the adult state that generally, or rather among 

 the superior animals, reproduction takes place. 



If we had only the observation of M. Sars on the Meduscef, 

 which are reproduced by buds in the state of larvse, the import- 

 ance of this character would already be considerably lessened ; 

 but several authors have pointed out examples of larvse which 

 produce and lay eggs. It must however be admitted that these 

 facts were badly interpreted. In our memoir on the Campanu- 

 larice, and more particularly in that on the Tubularia, we have 

 endeavoured to explain these phssnomena, by comparing the 

 ascertained facts with our own researches. 



M. R. Wagner J, one of the most able naturalists of Germany, 

 inserted in the ' Isis,^ in 1833, an observation of this kind which 

 he made on a Coryne from the Adriatic. Upon the side of the 

 body, M. Wagner observed a young Coryne developed of a form 

 quite difi*erent from that of its mother, and which produced eggs. 



M. Loven§, who has made so many beautiful observations of 

 late years on the inferior animals of the Baltic, has also furnished 

 an example of this kind of reproduction ; but instead of taking 

 the animal containing eggs for a young one, he regarded it, with 

 M. Ehrenberg, as an adult female. Figs. 12 and 13 A. illustrating 

 his memoir represent compartments in which are formed medusi- 

 form larvse, and, even in the midst of these larvse, ciliated eggs are 

 visible : figs. 2 and 7 B. furnish another example : the first con- 

 tains also eggs, the second represents a single larva. Cavolini|| 

 had observed the same phsenomenon ; he saw a young Pennaria 

 also produce ciliated eggs. 



We thus find several polyps in their young stage containing 

 eggs, and the chief reason which has led the author of this ge- 

 nus to believe his animal perfect loses all its importance. We 

 repeat, with M. de Quatrefages, that we must guard against pre- 

 mature general conclusions, since we every moment see fresh 



* Memoire sur I'Embryog^nie des Tubulaires. Bruxelles, 1844, p. 54. 



t Ann. Sc. Natur. vol. xvi. 2nd series. [Ann. Nat. Hist. vol. viii. p. 48. 

 —Ed.] 



X Isis, 1833, pi. 12. figs. 4, 6, 8. 



§ Verhand. der Kbnigl. Schwed. Academie, 1835. Wiegmann's Archiv, 

 t. V. 1837. Annal. des Sciences Natur. 2nd series, vol. xv. 1841. 



II Cavolini, Polyp. Mar., Napoli, 1785. 



