Van Beneden on the genera Eleutheria and Synhydra. 245 



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

 of sufficient imj)ortancc for us to recur to it ; for the opinion wliich 

 Ave then advanced has been confirmed by suVjsequcnt researches. 



Tlie 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 larvre ; 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 ])lace. 



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

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

 ance of this character would already be considerably lessened ; 

 but several authors have pointed out examples of larvre which 

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

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

 laritB, and more particularly in that on the Tubularice, we have 

 endeavoured to explain these phfenomcna, by comparing the 

 ascertained fiicts with our own researches. 



j\I. 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. AA'agner observed a young Coryne developed of a form 

 cjuite different from that of its mother, and which produced eggs. 



M. Loveni^, 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 exam])le : the first con- 

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

 had observed the same phsenomenon ; he saw a young Pennaria 

 also ])roduee ciliated eggs. 



^A e 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 rEmbryogenie des Tubulaires. Briixellcs, 1S44, p. 54. 



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

 —Ed.] 



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



$ Vcrhand. der Konigl. Schv/ed. Academie, 1S3.5. Wiegmann's Archiv, 

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



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



