PLATE 101. 



Hyalonema (Skianema) aequatoriale Lendenpeld. 

 Figures 1-3. 



1. — Radial section tlirough the marginal part of the sponge; magnified 20; phot. Zeiss, planar 20 mm.: 



a, gastral face; b, dermal face. 



2. — Radial section through the gastral membrane and the adjacent parts of the choanosome; magnified 



100; phot. Zeiss, apochr. 16, compens. oc. 6: 

 a, gastral pinule-fur; b, gastral membrane; c, small macramphidiscs protruding over the 

 gastral membrane; d, large macramphidiscs in the subgastral region. 



3. — Paratangential section through the gastral membrane, containing the zone occupied by the lateral 



rays of the pinules. 



Hyalonema (Skianema) umbraculum Lendenfeld. 

 Figures 4-17. 



4-7. — Microhexactines; magnified 200; phot. Zeiss, apochr. 8, compens. oc. 6. 



8, 9. — An abnormal large macramphidisc; magnified .500; phot. Zeiss, apochr. 8, compens. oc. 12: 



8, focussed high (on the uppermost teeth); 9, focu.ssed lower (on the shaft). 

 10. — Half (one anchor) of an abnormal large macramphidisc; magnified 500; phot. Zeiss, apochr. 8, 

 compens. oc. 12. 



11-13. — Parts of microhexactines (11, 13) and a whole one (12); magnified 500; phot. Zeiss, H. I. 



apochr. 2, compens. oc. 6. 

 14. — A diactine microhexactine-derivate; magnified 500; phot. Zeiss, H. I. apochr. 2, compens. oc. 6. 

 15-17. — Acanthophores; magnified 200; phot. Zeiss, apochr. 8, compens. oc. 6. 



