CHAPTER XV. 
THE SPONGES OF LAKE TANGANYIKA. 
The sponges which were obtained during the Tanganyika 
expeditions from that lake itself appear to consist of three 
distinct forms. Two of these new species were examined 
and described by Mr. Richard Evans under the names of 
Spongilla moorei and Spongilla tang any ikce ; but besides 
these among the material obtained during the first expedi- 
tion there were encountered the spicules of a third form 
embedded in the mud of the lake. The character of these 
spicules, it seems, might, with equal propriety, suggest that 
the sponge to which they belong is allied either to the New 
World genus, Uruguaya or to the Congo genus Potamolepis. 
As, however, nothing but the spicules had been obtained, 
Mr. Evans left the form unnamed. During the second 
Tanganyika expedition a small specimen of this third 
species was dredged alive from great depths adhering to a 
Paramelania shell, and this material was sent eventually to 
Herr Weltner in Berlin, who replies that the sponge is 
undoubtedly a new form, the framework being very similar 
to Spongilla bohmii. The sponge, however, still remains 
nameless, and as this is most inconvenient, I propose the 
specific term weltneri , leaving the form for the present as a 
member of the genus Potamolepis. 
