NUTRITION IN MEDUSA. 87 



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 elon- 

 gated 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, which terminates in the general 

 cavity of the stomach. The Medusa piilmo, of 

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

 belongs to this modern genus, and is now termed 

 the Rhizostoma 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. 



