PORIFEHA OF THE L.M.B.C. DISTRICT. 203 



Desmacidon tituJ>ans, Schmidt.* The length of the isolated 

 anisochelae in Esperella Jioveum 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 cheltie. '1 hey measure 0*008 — 0'016 mm. in length. 

 Possibly they are simply younger stages of the large ani- 

 sochelae and sigmata. 



In no other species of sponge did I ever see such great 

 masses of ova and developing embryos (morulse) as in 

 Esperella fi oven m. The ova are placed quite close to each 

 other so that one might almost speak of ovaries, and they 

 lie near to the limiting membrane, " in the position of 

 greatest security." The morulae 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 Esperella. These 

 authors found that in large and massive sponges, like 

 Esperella lapkiiformis, where the position of the ova and 

 embryos is a matter of no very great importance, so long 

 as they do not lie near to the surface, those elements are 

 scattered through the w^iole of the choanosome ; whilst 

 in a small and delicate species, like Esperella h/serialis, the 

 embryos take refuge in the centre of the spicular axis. 

 Further they state, that in Esperella mammiform is the em- 

 bryos are found grouped close to the stone to wliich 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., pi. xii.. fig. 24. 

 t Ridley and Dendy, loc. eit., p. 4. 



