CORONATE — PERIPHYLLA. 



545 



as the basal, central, aiul liuccal stomach. The central stomach is a 4-sidccl prism, the sides 

 being interradial and the angles [)erradial in position. I he lower or buccal part ot the stomach 

 hangs freely in the cavity of the bell, being joined to the subumbrella at 4 perradially situated 

 points at its inner end. There are 4 longitudinal, interradial, thickened regions in the wall 

 of the buccal stomach, which extend downward to the mouth-opening. The central stomach 

 is a wide cavity which communicates by 4 perradial openings with the gastrovascular space 

 of the subumbrella of the medusa. These 4 openings are narrow, elongate, longitudinal 

 clefts, and their edges are lined with numerous gastric cirri which project into the space ot 



Peripkylla hyacinthina. 



Fig. 342.~Aftcr Vanhoffen, in Valdivia Expedition. 



Fig. 343. — After Vanhoffen, in Nordisches Plankton. 



Showing variation in shape of bell. 



the stomach. The basal stomach is a 4-sided pyramid and 8 rows of gastric cirri extend 

 up the 4 sides near the angles to the apex of the pyramid where they meet. These rows ot 

 cirri are continuous with those surrounding the 4 perradial side-openings ot the central stomach. 

 The gastrovascular coronal sinus of the subumbrella is thus connected with that of the stomach 

 by the 4 perradially situated ostia of the central stomach. These open into this wide annular 

 cavity which occupies the mid-region of the subumbrella above the zone of circular muscles. 

 Below these, however, it appears as a broad, simple, annular space, which extends outward 



