PLATE 18. 



Staurocalyptus hamatus Lendenfeld. 

 Figures 1-14. 



1-4. — Two small discohexasters; magnified 2000; u. v. phot. Zeiss, q. monochr. 1.7, q. oc. 10: 



I, 2, one small discohexaster; 



1, focussed higher; 2, focussed lower; 

 3, 4, another small discohexaster; 



3, focussed higher; 4, focussed lower. 

 5, 6. — Views of the sponge after removal of the Dicranodromia; reduced 1: 9.85; phot. ZeLss, anastig. 

 480/412 mm.: 



5, from below; 



6, from above. 



7. — A small discohexaster; magnified 600; phot. Zeiss, H. I. apochr. 2, compens. oc. 6. 

 8-10. — Side-views of hypodermal pcntactincs; magnified 30; phot. Zeiss, planar 20 mm. 

 11, 12. — Part of a spicule-group; magnified 600; phot. Zeiss, H. I. apochr. 2, compens. oc. 6: 



II, focussed higher; 12, focussed lower; 



a, dermal rhabd; b, small discohexasters. 



13. — Part of a large rhabd of abnormal structure; magnified 600; u. v. phot. Zeiss, q. monochr. 6, q. oc. 10. 



14. — The sponge with the Dicranodromia seen from the front; natural size; phot. Zeiss, anastig. 



480/412 mm. 



Holascus edwardsii Lendenfeld. 

 Figures 15-26. 



15. — Group of slender-rayed comital triactines; magnified 30; phot. Zeiss, planar 20 mm. 



16. — Group of slender-rayed comital triactines, tetractines, and pentactines; magnified 50; phot. 



Zeiss, apochr. 16, compens. oc. 4. 



17. 18. — Hypogastral hexactines; magnified 50; phot. Zeiss, apochr. 16, compens. oc. 4. 

 19-21. — Hypodermal hexactines; magnified 50; phot. Zeiss, apochr. 16, compens. oc. 4. 



22. — Surface-view of the skeleton of the body-wall. The soft parts and most of the smaller spicules are 



removed. The large choanosomal pentactines are still nearly in their natural position. Magni- 

 fied 7.5, phot. Zeiss, planar 50 mm. : 



a, large choanosomal pentactines; b, comitals. 



23. — The central part of a slender-rayed, comital spicule with two fully developed long rays, one con- 



siderably reduced ray, and two insignificant ray-rudiments which appear as slight protuberances; 

 magnified 600; phot. Zei.ss, apochr. 4, compens.-oc. 12. 

 24-26. — The distal part of the distal ray of three hypodermal hexactines; magnified 600; phot. Zeiss, 

 apochr. 4, compens. oc. 12. 



