PLATE 76. 



Hyalonema (Prionema) agujanum tenuis Lendenfeld. 



Figs. 1-7, 11, 12, 15-36 — form A. 

 Figs. 8-10, 13, 14 —form B. 



1. — The centrum and one ray of a microhexactine of form A; magnified 2000; u. v. phot. Zeiss, q. 



monochr. 1.7, q. oc. 10. 



2, 3. — Micramphidiscs of form A; magnified 500: 



2, phot. Zeiss, H. I. apochr. 2, compens. oc. 6; 



3, phot. Zeiss, apochi'. 4, compens. oc. 12. 



4-6. — Portions of transverse sections of a Palythoa polyp attached to the stalk of a specimen of form A; 



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

 7. — Axial, longitudinal section through the upper part of the stalk with Palythoa attached, and the 



lower part of the body of form A; magnified 6; phot. Zeiss, planar 50 mm. 

 8-14. — Acanthophores from the sponge; magnified 200; phot. Zeiss, apochr. 8, compens. oc. 6: 



8, a small regular tetractine of form B; 



9, a large regular pentactine of form B; 



10, a large u-regular tetractine of form B; 



11, 12, small regular tetractines of form A; 



13, a large regular tetractine of form B; 



14, a large diactme of form B. 



15-32. — Acanthophores and other sponge-spicules formed in a Palythoa polyp on the stalk of a speci- 

 men of form A; magnified 200; phot. Zeiss, apochr. 8, compens. oc. 6: 



15, 16, short diactines, much more spmy at the ends than in the middle; 

 17-20, short and stout rod-shaped spicules; uniformly spined throughout; 

 21, 22, small stout triactines; uniformly spined throughout; 



23-30, small stout tetractines, uniformly spined throughout; 



31, a small only terminally spined tylostyle; 



32, a minute pentactine. 



33. — The tip of an anchor-tooth of a large serrated mesamphidisc of form A; magnified 2000; u. v. 



phot. Zeiss, q. monochr. 1.7, q. oc. 10. 



34. — Transverse section through the upper part of a Palythoa polyp attached to the stalk of a specimen 



of form A; magnified 30; phot. Zeiss, planar 20 mm. 



35. 36. — The end-part of an anchor-tooth of a large mesamphidisc of form A; magnified 2000; u. v. 



phot. Zeiss, q. monochr. 1.7, q. oc. 10: 

 35, focussed higher; 36, focussed lower. 



