Elements of zoology, or, Natural Elements of zoology, or, Natural history of animals / ed. by Reese elementsofzoolog00rees Year: 1849 40S ZOOLOGY. of a large umbrella-shaped disk, from the under surface of which hang down four broad and long tentacula. Both disk and tentacula exhibit a very beautiful assemblage of colours, like those of the rainbow, when the rays of the sun are reflected from their surface. On the under side of the disk is seen the mouth, situated in the centre, and surrounded by the origins of the tentacula. This is the entrance to a stomach, which lies in the middle of
Elements of zoology, or, Natural Elements of zoology, or, Natural history of animals / ed. by Reese elementsofzoolog00rees Year: 1849 40S ZOOLOGY. of a large umbrella-shaped disk, from the under surface of which hang down four broad and long tentacula. Both disk and tentacula exhibit a very beautiful assemblage of colours, like those of the rainbow, when the rays of the sun are reflected from their surface. On the under side of the disk is seen the mouth, situated in the centre, and surrounded by the origins of the tentacula. This is the entrance to a stomach, which lies in the middle of the disk, and is surrounded by four ovarial chambers, having separate external orifices. The animal may thus be compared, in some degree, to a sea-anemone detached from its base, and swimming with its mouth downwards. The membrane of the disk extends much beyond the stomach and ovarial chambers (which may be described as occupying the part corresponding to that included between the metallic stretchers of the umbrella) ; and this broad, free margin is endowed with muscular powers, and performs a series of re- gular undulations, by which the animal is propelled through the water. Medusa : A, under surface, showing the mouth in the centre, surrounded by the tentacula, and the ovarial chambers exterior to the origins of these; B, side view, showing the tentacula hanging down in their natural position 874. The extreme softness of the tissues of these Medusa is an obvious reason why they should not expose themselves to the rough surface of the ocean, where they would be beaten to pieces by the waves, or to the proximity of the shore, from which they would soon receive fatal injury. Although so soft, how- ever, they have the power of mastering prey of much firmer structure ; and hard Crustacea, as well as other marine animals of higher organization, supply them with food. It is probable that the stinging power with which the tentacula are furnished, assists them in mastering some
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