THE TANGANYIKA PROBLEM. 



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stiffly arrayed above the bell in the manner represented in 

 Fig. 1. It is a truly pelagic form, being often encountered 

 in the deep open water of Lake Tanganyika, where it is 

 seen slowly pulsating at all depths, and during life is so 

 glassy as to be almost invisible. Its chief anatomical peculi- 

 arities are constituted by the broadness and shortness of the 



Fig. I. — Using asexual adult of the Tanganyika 

 medusa, enlarged about one-third. To the right 

 is seen a string of buds becoming detached. 



manubrium, the diameter of which is generally about two- 

 thirds that of the whole disc. It is also so short that, when 

 the animal is alive, it does not project beyond the velum. 

 In association with these peculiarities we have a great 

 development of mesoglea, forming the large lens-shaped 

 mass that partially fills up the gastric cavity, and which, by 

 its transparency, gives the organism the form of a ring 



