E. W. BERGER ON THE UUBOMKDUS/U. o 



interradii. Half way between any two points of attachment of the 

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

 margin of the bell (cube), in a niche, hang the sensory clubs, one on 

 each side, four in all. Each sensory club hangs in a niche of the 

 exumbrella and is attached by a small peduncle whose axial canal 

 is in connection with one of the four stomach-pockets and in the 

 club proper forms an ampulla-like enlargement. 



Each club is said to lie in a perradius, and, like the tentacles, 

 belongs to the subumbrella. This is shown by the course of the 

 vascular lamellae, bands of cells that, stretching through the jelly 

 from the endoderm to the ectoderm all around the margin, form the 

 line of division between sub- and exumbrella. 



Each club has six eyes. Two of these on the middle line of the 

 club facing inwards are called the proximal and distal complex eyes, 

 to distinguish them from the four simple eyes that are disposed 

 laterally, two on each side of the line of the two complex eyes. All of 

 these eyes look inwards into the bell cavity through a thin transparent 

 membrane of the subumbrella. Besides the eyes and the ampulla 

 already mentioned, a concretion fills the lowermost part of the club, 

 and a group of large cells, having a network-like structure and called 

 network cells by Conant, fill the uppermost part of the club between 

 the proximal complex eye and the attachment of the club to its 

 peduncle (Plate II, Fig. 13). What is evidently nerve tissue, fibers and 

 ganglion cells, fills the rest of the club, with two groups of large 

 ganglion cells disposed laterally from the network cells. A sensory 

 (flagellate) epithelium covers the club. 



Most Cubomedusse, among them Charybdea, have a velarium 

 (comparable to the velum of the -Hydromedusae), a membrane of 

 tissue that extends inwards at right angles all around the margin. 

 This velarium, like a velum, has a central opening through which 

 the water is expelled from the bell-cavity when the animal pulsates. 

 In the perradii and in the angle between the velarium and the body 

 wall, are the frenula, which give support to the velarium much like 

 brackets support a shelf, except that here the brackets are above the 

 shelf instead of below. 



In the upper part of the bell is the stomach, with the phacelli in 

 its interradii, and continued ventrally into the manubrium, or the 

 proboscis. The cavity of the stomach is continued in the perradii 

 through the four gastric ostia into the four stomach pockets, which 



