PLATE 28. 



Hexactinella monticularis Lendenfeld. 

 Figures 1-28. 



1-4. — Four scopules; magnified 300; phot. Zeiss, apochr. 4, compens. oc. 6. 



5-7. — The centres and end-rays of three scopules; magnified 2000; u. v. phot. Zeiss, q. monochr. 1.7, 

 q. oc. 10. 



8, 9. — The centre of a scopule; magnified 2000; u. v. phot. Zeiss, q. monochr. 1.7, q. oc. 10: 

 8, focussed higher; 9, focussed lower. 



10. — Part of an uncinate; magnified 2000; u. v. phot. Zeiss, q. monoclir. 1.7, q. oc. 10. 



11, 12. — Parts of discohexasters; magnified 2000; u. v. phot. Zeiss, q. monochr. 1.7, q. oc. 10: 



11, the end of an end-ray of a small discohexaster seen obliquely from above; 



12, an entire end-ray of a large discohexaster. 



13, 14. — The centimes and end-rays of two scopules; magnified 300; phot. Zeiss, apochr. 4, compens. oc. 6. 

 15, 16. — Two large discohexasters; magnified 300; phot. Zeiss, apochr. 4, compens. oc. 6. 

 17, 18. — Parts of long-spined hexactines; magnified 200; phot. Zeiss, apochr. 8, compens. oc. 6. 



19. — Apical view of a superficial pentactine; magnified 200; phot. Zeiss, apochr. 8, compens. oc. 6. 



20. — Part of a small discohexaster; magnified 2000;_ u. v. phot. Zeiss, q. monochr. 1.7, q. oc. 10. 



21. — Part of the superficial skeleton-net (pentactines soldered together); magnified 200; phot. Zeiss, 



apochr. 8, compens. oc. 6. 



22. — Part of a beam of the skeleton-net with a spine; magnified 200; phot. Zeiss, apochr. 8, compens. 



oc. 6; 



23. — The skeleton-not of part of a specimen; magnified 3.5; phot. Zeiss, planar 100 mm. 



24. — Part of a transverse section through a superficial portion of the skeleton; magnified 20; phot. 



Zeiss, planar 20 mm.: 



a, internal skeleton-net; b, spines protruding towards the surface. 



25. — Group of discohexasters from a spicule-preparation; magnified 300; phot. Zeiss, apochr. 4, com- 



pens. oc. 6. 



26. — Portion of the inner, sectioned face of a skeleton-net cut longitudinally in half; magnified 6.6; 



phot. Zeiss, planar 50 mm. 



27. — Part of the superficial skeleton-net (pentactines soldered together); magnified 200; phot. Zeiss, 



apochr. 8, compens. oc. 6. 



28. — Surface-view of the skeleton-net of one of the monticular protuberances of the surface; magnified 



6.6; phot. Zeiss, planar 50 mm. 



