94 Miss J. Stephens on new 
Fig. 7. Mamillopora bidentata, Reuss, x 25. Showing the primary 
zocecium and the six surrounding zocecia. From Bocca di 
Sciesa. 
Fig. 8. Conescharellina eocena, Neviani, x 10.. Section from Spiassi, 
N. Italy. 
Fig. 9. Batopora multiradiata, Rss., x 25. Showing ovicells. From 
Monitecehio Maggiore. 
Fg. 10. Ditto. x 10. Showing the formation of a second layer from 
the neighbourhood of the pit. Frm Val di Lonte. 
ago Ni. Mamillopor a bidentatu, Reuss, X 25. Showing ovicell. From 
Bocca di Sciesa. (a) zoarium, X 3. 
Eg. 12. Conescharellina eocena, Neviani, X 25. This figure is built up 
from various parts, as the preservation as a whole is not 
perfect. From Spiassi. 
VIIL—Two new ge Freshwater Sponges. = JANE 
Srepuens, B.A., B.Sc., National Museum of Ireland. 
SEVERAL years ago Dr. Annandale (5) drew attention to the 
somewhat oyster- like shells‘of the genus theria as affo-ding 
a favourable starting-place for the growth of freshwater 
sponges, not only on account of their roughened and often 
corrugated surface, but also owing to the fact that, like true 
oysters, their lower valve is firmly fixed to some solid support. 
Dr. Annandale stated that at least one species of freshwater 
sponge, Corvospongilla loricata (Weltner), had already heen 
described from an theria shell, when an examination of the 
shells belonging to this genus in ‘the collections of the Indian 
Museum led him to the discovery of two new species of 
sponges. He remarked that he had little doubt that other 
sponges would be brought to light if the #theria shells 
preserved in museums were carefully scrutinized. Following 
Annandale’s suggestion, the Mtheria shells in the 
collection of this museum were examined, with the result 
that two well-marked new species were discovered on one 
shell, and afew broken gemmules, too fragmentary to identify, 
on another. 
As is well known, the genus 4theria occurs only in Africe 
and in the north-west part of Madagascar. On the continent 
of Africa it is confined to the tropics, except that it descends 
the River Nile to the mouth. Many species have been 
described from time to time, but the researches of Drs. An- 
thony and Germain (6, p. 372) have shown that there is only 
one species—a very polymorphic one, namely Atheria ellip- 
tica, Lamarck. Two varieties are, however, recognized by 
these authors— AE. elliptica, var. typtca, Germain, a smooth 
