434 
CHARLES L. BOULENGER. 
structure of the nettle-ring, or of the arrangement of the 
sense-organs. 
A small piece of the manubrium is attached to the umbrella, 
and shows that this individual is also a female ; the ovary, 
however, seems but poorly developed. 1 
In all four medusae the tentacles are in a good state of 
preservation, and in their structure very closely resemble 
those of Limnocnida tanganicae. As in that species the 
larger tentacles are attached to the exumbrella surface of the 
bell for a considerable distance (Text-fig. 2) ; they are, however, 
not deeply imbedded in the jelly as in the Victoria Nyanza 
specimens described by Gunther ( 10 ), nor could I find distinct 
projecting supports, such as Browne figures in the medusae 
collected by Budgett in the R. Niger (S). 
The nematocysts are of the same size and shape as those of 
L. tanganicae, and are grouped in distinct batteries, which on 
the extended tentacles are irregularly distributed and situated 
at the extremities of conspicuous papillae (PL 42, fig. 3), 
recalling those which occur on the tentacles of another well- 
known freshwater medusa, Limnocodium sowerbii. 2 As 
in the Tanganyika species, the nematocyst batteries are absent 
from the proximal parts of the tentacles, in which position 
however, numerous isolated stinging-cells are to be seen 
making their way to the more distal parts. In the largest 
tentacles quite a third of the organ is free from nematocyst 
batteries, and even the smallest have these structures absent 
from at least a small basal portion. 
The above account of the medusae collected by Mr. Thomas 
makes it evident that the two species of Limnocnidaare 
closely allied to one another, and agree in many essential 
features. L. rhodesiae can, however, be readily distinguished 
from L. tanganicae by the structure of its umbrella-margin 
1 The two gonad- bearing medusse were obtained by Mr. Thomas in 
December, 1908. 
2 C f . E. T. Browne, “ On the Freshwater Medusa liberated by 
Microhydra ryderi, Potts, and a Comparison with Limnocodium, 
‘ Quart. Joum. Micr. Sci.,’ vol. 50, 1906, pi. 37, fig. 3. 
