Berger, Eyes of Ciibomedusce. 223 



and show much variation in size and appearance in correspond- 

 ence with the phases of activity of these cells. The ducts from 

 these sacks are the channels by which the secretion is conveyed 

 to the surface of the animal. The radiating threads surround- 

 ing the sacks are probably continuations of the reticulum of the 

 cytoplasm. 



The Histological Structure of the Eyes of Cubomedus^. 



By Edward W. Berger. 



While in Jamaica with the Johns Hopkins Marine Labora- 

 tory, during the summer of 1897, Dr. Conant preserved mater- 

 ial and tried experiments for the purpose of continuing his re- 

 search on the Cubomedusas, begun the year previous and now 

 published as his thesis by the University. Upon the unfortu- 

 nate death of Dr. Conant this material and notes were placed 

 in the present writer's hands by Dr. Brooks. It is intended 

 in the following paper to give only the principal results ob- 

 tained by a careful study on the histology of the eyes of these 

 medusae, leaving their fuller discussion, together with Conant's 

 physiological notes, for a more complete paper. The present 

 work was done wholly on Charybdea xaymacana, while Co- 

 nant's own work was in part done on Tripedalia. 



For a complete description of the anatomy of the Cubo- 

 medusse Dr. Conant's thesis, "The Cubomedusae," or the 

 "Johns Hopkins University Circulars," No. 132, November, 

 1897, should be consulted. 



Roughly speaking, the Cubomedusae, as the the name im- 

 plies, are cubes with their tentacles (four in Charybdea but 

 twelve in Tripedalia) arranged at the four corners of the lower 

 face of the cube. These tentacles are said to lie in the interradii. 

 Half way between any two points of attachment of the pedalia 

 (the basal portions of the tentacles) and a little above the lower 

 margin of the bell, hang the sensory clubs, one on each side, 



