SOME NEW SCYPIIOMEDUSjE OF JAPAN. 7 



endoderm cells. The gelatinous layer is thickest in the pyloric 

 portion. 



The subumbrella is broader than the exumbrella. Its surface 

 is wavy for the greater part, but rugose near the umbrella margin 

 as well as in the perradial regions. The rugose portion near the 

 umbrella margin is often turned over towards the aboral side. 

 The rugosity is caused by large groups or glands of nematocysts 

 lying underneath. The subumbrella also consists of the three 

 layers. Its ectoderm cells are higher than those of the ex- 

 umbrella and many of them are in possession of nematocysts. 

 The gelatinous layer is exceedingly thin. 



The umbrella cavity is hardly distinguishable. The very 

 small interradial concavities found in the central disc of the 

 body may be compared to the infundibular deepenings of other 

 Stauromedusse. 



The interradial, longitudinal muscles are well developed. 

 They run between the adradial bunch of tentacles and the pylorus, 

 without extending into the peduncle. 



The coronal or marginal muscle is cut into eight separate 

 pieces, each of which is shaped either like the letter U or V. 

 The perradial pieces are much longer and broader than the 

 interradial pieces. 



The eight adradial lobes are united in pairs, giving to the 

 animal the form of a Greek cross. The distal end of each 

 adradial lobe is pointed, bent at a right angle to the remaining 

 part and turned towards the oral side. Each united pair of the 

 adradial lobes may be longitudinally folded, as it were, on the 

 oral side. Moreover it may be bent towards the mouth. It is 

 longer than the diameter of the central undivided portion of the 

 umbrella. 



