ON AN AFRICAN MEDUSA. 71 



5. On a Freshwater Medusa from the Limpopo River 

 System, with a Note on a Parasitic Infusorian. By 

 (t. Arnold, M.Sc, A.R.C.S., Curator of the Rhodesia 

 Museum, Bulawayo, and C. L. Boulengtcr, M.A., 

 D.Sc, F.Z.S., Zoological Department, The University 

 of Birmingham. 



[Received December 1, 1914; Read March 0, 1915.] 

 (Plate I * and Text-figures 1 & 2.) 



Index. 



Pnaje 



Anatomy of Limnocnida rhodesice 73 



Tricliodina parasitic on Limnocnida spp 75 



Limpopo It. Si'stem, occurrence of Limnocnida rhodesice 71 



The medusae which form the subject of this communication 

 were obtained by one of the authors during* January 1913 in 

 the Norquane River, a minor tributary flowing through the 

 Inziza and Umzingwane Rivers to the Limpopo. They were 

 identified as belonging to the genus Limnocnida, and the new 

 fact in the. distribution of this form was recorded in a letter to 

 ' Nature ' in April of the same year (17). 



A number of specimens were sent to England, and proved to 

 belong to the same species, Limnocnida rhodesice Boulenger, as 

 those collected during 1908 by Mr. R. H. Thomas in the 

 llunyani River, a southern tributary of the Middle Zambesi. 



Limnocnida rhgdesim was described in 1912 (14) from some- 

 what scanty and poorly preserved material, so that, in addition 

 to their interest from the zoo-geographical point of view, the 

 Norquane River specimens afford an opportunity of adding to 

 our knowledge of this species. 



Species of the genus Limnocnida have now been recorded from 

 the five principal river-systems of Africa,, as well as from India. 

 The type species, L. tanganicce, discovered by Bbhm (1) in Lake 

 Tanganyika, in 1883 and described by Giinther ten years later 

 (2, 3), has been found to occur also in the Victoria Nyanza (6-8) 

 as well as in the River Niger (9, 10). Lj. rhodesice is now known 

 to inhabit Rhodesia both in the Zambesi a,nd Limpopo river- 

 systems ; and the Indian species has been described under the 

 name of L. indica (15) from tributaries of the Kistna River in 

 the Satara district of the Bombay Presidency. 



The Norquane River is situated in the Bembesi district of 

 Southern Rhodesia, about 30 miles W.N.W. of Bulawayo. This 

 stream usually contains water throughout the year, but the 

 visible flow is interrupted during the dry season by sandy bars, 

 whereby the course is broken up into a, succession of pools. 



* For explanation of the I'l.-itf sec p, 7l>. 



