NUTRITION IN MEDUSiE. 87 



to distribute the nutritious juices to every part 

 of the organization. 



There are other species of Medusae, com- 

 posing the genus Rhizostoma of Cuvier, which, 

 instead of having only one mouth, are provided 

 with a great number of tubes which serve that 

 office, and which bear a great analogy to the 

 roots of a plant.* The pedicle terminates below 

 in a great number of fringed processes, which, 

 on examination, are found to contain ramified 

 tubes, with orifices opening at the extremity of 

 each process. In this singular tribe of animals 

 there is properly no mouth or central orifice ; 

 the only avenues to the stomach being these 

 elongated canals, which collect food from every 

 quarter where they extend, and which, uniting 

 into larger and larger trunks as they proceed 

 towards the body, form one central tube, or 

 oesophagus, terminating in the general cavity 

 of the stomach. The Medusa pulmo, of which 

 a figure was given in Vol. i., page 192, belongs 

 to this modern genus, and is now termed the 

 JRhizostoma Cuvieri. 



The course of these absorbent vessels is most 

 conveniently traced after they have been filled 

 with a dark coloured liquid. The appearances 

 they present in the Rhizostoma Cuvieri, after 



* It is from this circumstance that the genus has received the 

 name it now bears, and which is derived from two Greek words, 

 signifying root-like mouths. 



