AND THE LOWEE ANIMALS. 151 



published their beautiful researches. The former, who 

 was a native of Bergen and a clergyman, devoted his 

 leisure hours to the study of the rich marine fauna of 

 the Norwegian coasts. In 1820 he described two 

 polyps akin to Hydra as new species, giving them 

 the names of 8cyp1iisioma and Strobila; but he after- 

 wards (1833) discovered that the second of these 

 creatures was only a transformation of the first. In 

 1835 he stated that the strobila produces genuine 

 acalephse, by a process which till then had been 

 unobserved.* On his side, Siebold, who was one of 

 the first of German naturalists to perceive the import 

 of marine creations, clearly distinguished the sexual 

 organs of the Medusas, watched the first transforma- 

 tions of the larvge which proceeded from the ova, and 

 saw them converted into true polyps, f Finally, Saars, 

 in a memoir, J which was soon translated into every 

 European language, co-ordinated and completed this 

 history, which till then had been in but a fragmentary 

 condition. We shall now give a short sketch of the 

 results which have been arrived at. 



The red Aurelia (Medusa aurita), which Ehrenberg's 

 writings have made almost as celebrated, as those of 

 Lyonnet the willow-moth, § is a pretty creature, with 



* " Beskrivelser og Jattagelser over nogle moerkelige eller nye 

 i Havet ved den Bergenske kyst levende Dyr," A portion of this 

 work was translated by M. Gervais in the " Annales d'Anatomie 

 et de Physiologie " for 1838. 



t " Beitrage zur Naturgeschichte der wirbellosen Thiere." 



% " Memoire sur le Developpement de la Medusa aurita, et de la 

 Cyanea capillata," in the "Annales des Sciences naturelles" for 1841. 



§ The organization of medusae had been considered very simple 

 till this work appeared in 1839, in the Memoirs of the Berlin 

 Academy. It was thought that the cavities and canals which 



