274 On the Fresh water Jfedusa of Lake Tanganyika. 



wall of the manubrium. I hope, however, to be able to 

 supply further details of this interesting process of bud- 

 formation in a subsequent paper. 



As the Tanganyika Medusa is still without a generic name, 

 1 propose that of Limnocnida for it, with the following cha- 

 racters : — 



Limnocnida, gen. nov. 



Umbrella flat, almost disk-like, about four times as broad 

 as high, with a lens-shaped thickening in the middle. Ten- 

 tacles very numerous, hollow, with bases partly imbedded in 

 and adnate to the umbrella margin. Marginal sense-organs 

 situate along line of attachment of velum, composed of a 

 multicellular mass of refringent cells enclosed in a roundish 

 capsule. Mouth round, two thirds the diameter of animal. 

 Manubrium very short. Stomach shallow, of same diameter 

 as mouth. Radial canals four. Reproduction by budding. 

 Sexual organs situated on the manubrium. 



Limnocnida tanganjicce (Bohm). 



Size : diameter of umbrella | inch. 

 Loc. Lake Tanganyika. 



As my knowledge of the significance of several points 

 observed in the general anatomy of this freshwater Medusa is 

 as yet very imperfect, I must reserve a more detailed account 

 of these, as well as all discussion of the probable affinities and 

 systematic position of Limnocnida^ for another paper. If a 

 place has to be found for Limnocnida in Haeckel's System of 

 Medusae we are beset with almost the same difficulties as those 

 which presented themselves in the case of Limnocodium. The 

 same battle will have to be fought over again, only the field 

 is changed. Those who considered Limnocodium to be one 

 of the Lcptoinedusge will refer Limnocnida to the Antlio- 

 medusEe, while those who regarded Limnocodium as one of 

 the Trachomedusas will have to place Limnocnida among the 

 NarcomedusaB. 



EXPLANATION OF THE PLATES. 

 Plate XIII. 



Fig. 1. Side view of Liimiocnida tanganjicce, X 4. 



Fig. 2. Ventral view of ditto, X 3. 



Fig. S. Ventral view of a portion of the peripliery of the disk, X 0. 



