JtEDUSiE OR JELLT-nSH. 37 



animal substances of larger dimensions, are imbibed, and form 

 the nutriment of tlie animal. In the genus Cyanea, Avhich is 

 so extremely abundant on our coast, the food is taken by one 

 four-lipped mouth, and is of a coarser kind, consisting prin- 

 cipally of Crustacea and small fishes. A provision for throwing 

 oil" the undigested portions is therefore required, and we ac- 

 cordingly find that no less than eight canals load from the. 

 centre of the disc to the outer margin, and are appropriated 

 exclusively to this use; an apparatus which, in the other 

 genus, was not wanted, and which, accordingly, had no 

 existence. 



To the minute and laborious researches of modern natu- 

 ralists, we are indebted for a knowledge of the fact, that the 

 sexes in these animals aie separate, and that the ova, or eggs, 

 imdergo a singular and highly interesting series of trans- 

 formations before assuming the likeness of the parent. 



The species of Medusa most abundant on our coasts during 

 the early part of the summer (^Cyanea auritci) is well known 

 by the four conspicuous lunar or heart-shaped figures which 

 it exhibits. These are of a pinkish or pui-plish colour, and 

 are, in fact, the ovaries. Four pouches are observed on the 

 lower surface of the body. To these the young, at a certain 

 period, are transferred from the ovaries, and undergo a 

 species of development analogous to that of the young qua- 

 drupeds of Australia in the marsupial pouch of the mother. 

 After changes in their size and colour, they exhibit a change 

 of form, become clothed with vibratile cilia, and, leaving the 

 maternal pouch, swim freely about, the larger extremity being 

 always in advance {Fig. 21). The little creature soon at- 



21. 88. 23. 24- 



Developxe:it of the MEorsf. 



taches itself to some fixed object {Fig. 22), and four arms 

 appear, surrounding a central mouth {Fig. 23). The arms 

 lengthen, four additional ones are developed, all are highly con- 

 tractile, covered with cilia, and actively employed in the capture 



