NUTRITION IN MEDUSiE. 



67 



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 num- 

 ber of fringed processes, which, on examination, are found 

 to contain ramified tubes, with orifices opening at the ex- 

 tremity of each process. In this singular tribe of animals 

 there is properly no mouth or central orifice, the only ave- 

 nues 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, 

 which terminates in the general cavity of the stomach. The 

 Medusa pulmo, of which a figure was given in Vol. i., page 

 142, belongs to this modern genus, and is now termed the 

 Rhizostovia Cuvieri, 



The course of these absorbent vessels is most conveni- 

 ently traced after they have been filled with a dark coloured 

 liquid. The appearances they present in the Rhizosioma 



* It is from this circumstance tliat the g-eniis has received the name it now 

 bears, and wiiich is derived from two Greek words, signifying root-like 

 mouths. 



