126 



THE HARMONIES OF NATURE. 



description. The Discophora are distinguished by a watch-glass 

 or bell-shaped body, generally pellucid, from the lower surface 

 of which various processes and filaments depend ; but there are 

 very many modifications in the structure of the various species. 

 The Medusae, for instance, are provided with a large central 

 mouth, leading directly into the stomach, and surrounded 

 by four brachial appendages, while numerous slender fibres or 

 tentacula hang from the border of the umbrella-shaped disk. 



The Khizostomata, on the 

 other hand, have no tenta- 

 cles round the margin of the 

 disk, but are furnished with 

 eight arms in the centre pro- 

 ceeding from a common stalk, 

 and instead of a central oral 

 opening, we find here each 

 arm traversed by channels 

 (c), leading to the digestive 

 cavity (a), and dividing into 

 numerous branches with nar- 

 row openings at the lower ex- 

 tremity (d). Through these 

 minute apertures nourish- 

 ment is received, which 



consequently must consist of very small animals indeed. 

 On injecting milk into the oral cavity of the Discophora, 

 vessels symmetrically arranged in a radiate manner, and 

 divisible by four, become apparent, which, proceeding to 

 the margin of the disk, there terminate in a circular vessel, 

 which is supposed to be a respiratory organ. Small reddish 

 or brownish eyes and tiny vesicles containing a limpid fluid 

 and chalky otolithes arranged along the margin of the disk, com- 

 municate the impressions of light and sound, and the sudden 

 retraction of their tentacles when seizing their prey sufficiently 

 proves them to be possessed of a high degree of sensitiveness. 



Thus on a closer examination we find that the despised sea- 

 blubbers, from which even a naturalist like Reaumur turned 

 with contempt as from mere lumps of animated jelly, possess 

 in reality a highly interesting organisation, and our admiration 

 increases when we find that creatures endowed with con- 



Rhizostoma. 



