PLATE 45. 



Hyalonema (Hyalonema) agassizi Lendenfeld. 



Figs. 1-38, 40-49 — form A, Station 4656. 



Figs. 39, 62-64 —form D, Station 3684 (A. A. 17). 



Figs. 50-53 —form B, Station 4651. 



Figs 54-61 — form C, Station 4740. 



1-4. — Stout-rayed tetractine acanthophores of the spicule-cement in the basal part of form A; magnified 



100; phot. Zeiss, apochr. 10, compens. oc. 6. 

 5. — Part of a rhabd acanthophore of the spicule-cement of the basal part of form A; magnified 100; 



phot. Zeiss, apochr. 16, compens. oc. 6. 

 6-13. — Hexactine megascleres of form A; magnified 50; phot. Zeiss, achr. aa, compens. oc. 6: 

 6-8, 11, small ones; 

 9, 10, large ones; 

 12, 13, medium-sized ones. 

 14-17. — Stout-rayed acanthophores of the cement in the basal part of form A; magnified 100; phot. 

 Zeiss, apochr. 16, compens. oc. 6: 

 14, 15, tetractmes with one ray strongly reduced; 

 16, 17, diactine tetractine-derivates. 

 18. — Section vertical to the surface through a superficial part of form A; magnified 20; phot. Zeiss, 

 planar 20 mm.: 



a, dermal membrane with pinule-fur. 

 19-22. — Rhabds of the choanosome of form A; magnified 50; phot. Zeiss, achr. aa, compens. oc. 6: 



19, 21, 22, amphioxes; 



20, a tylostyle. 



23. — Section vertical to the surface through a superficial part of form A; magenta; magnified 100; 



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

 a, dermal pinule-fur. 



24, 25. — Stout-rayed tetractines, with rays strongly reduced in length, of the spicule-cement in the basal 



part of form A; magnified 300; phot. Zeiss, apochr. 4, compens. oc. 6. 



26-34. — Spheres of the basal part of form A; magnified 300; phot. Zeiss, apoclir. 4, compens. oc. 6. 



35, 36.— Stout-rayed tetractine acanthophores of the spicule-cement of the basal part of form A; magni- 

 fied 300; phot. Zeiss, apochr. 4, compens. oc. 6: 



35, a young one; 



36, an adult one. 



37. — A stout-rayed triactine acanthophore from the spicule-cement of the basal part of form A; magni- 



fied 300; phot. Zeiss, apochr. 4, compens. oc. 6. 



38. — A stout-rayed pentactine acanthophore with rays I'educed in length, froni the spicule-cement in 



the basal part of form A; magnified 300; phot. Zeiss, apochr. 4, compens. oc. 6. 



39. — A stout-rayed tetractine acanthophore from the spicule-cement in the basal part of form D; magni- 



fied 30; phot. Zeiss, apochr. 4, compens. oc. 6. 

 40-64. — Amphidiscs; magnified 500; phot. Zeiss, H. I. apochr. 2, compens. oc. 4: 

 40-45, small micramphidiscs of form A; 

 46-49, large micramphidiscs of form A; 

 50-52, small micramphidiscs of form B; 

 53, small macramphidisc of form B; 

 54-58, small micramphidiscs of form C; 

 59-61, large micramphidiscs of form C; 



62, small micramphidisc of form D; 



63, 64, large micramphidiscs of form D. 



