PORIFERA OF THE L.M.B.C. DISTRICT. 203 
Desmacidon titubans, Schmidt.* The length of the isolated 
anisochele in Hsperella floreum is 0°036 mm. Besides 
those microscleres we find also simple sigmata, 0°06 mm. 
in length. Lastly there appeared to be present also a 
most minute kind of microscleres, but, on account of their 
smallness, I could not make out whether they were sigmata 
or chele. ‘lhey measure 0°008—0:016 mm. in length. 
Possibly they are simply younger stages of the large ani- 
sochele and sigmata. ; 
In no other species of sponge did I ever see such great 
masses of ova and developing embryos (morule) as in 
Esperella floreum. 'The ova are placed quite close to each 
other so that one might almost speak of ovaries, and they 
he near to the limiting membrane, ‘‘in the position of 
greatest security.” The morule are nearer to the surface. 
It was interesting to me to find that the greatest part of 
Ridley’s and Dendy’s ‘‘ Embryological Notes” + is taken 
from the examination of some species of H’sperella. These 
authors found that in large and massive sponges, like 
Esperella lapidiformis, where the position of the ova and 
embryos is a matter of no very great importance, so long 
as they do not he near to the surface, those elements are 
scattered through the whole of the choanosome; whilst 
in a small and delicate species, ike Esperella biserialis, the 
embryos take refuge in the centre of the spicular axis. 
Further they state, that in Hsperella mammiformis the em- 
bryos are found grouped close to the stone to which the 
sponge is attached, near the centre of the base. 
Our species has been recorded by Bowerbank from East 
Loch, Tarbet, Harris, and Strangford Lough. 
* Carter, ‘‘ Ann. and Mag. Nat. Hist., ser. 5, vol. ix., pl. xii., fig. 24, 
+ Ridley and Dendy, loc. cit., p. 4, 
