PLATE 75. 



Hyalonema (Prionema) agujanum tenuis Lendenfeld. 



Figs. 1-13, 15, 17, 19-27, 29-37— form A. 

 Figs. 14, 16, 18, 28 —form B. 



1, 2. — A small serrated mesamphidisc of form A; magnified 500; phot. Zeiss, apochr. 4, compens. oc. 12: 

 1, focussed higher (the uppermost teeth in focus) ; 2, focussed lower (the centre of the shaft in focus). 



3-21. — Macramphidiscs; magnified 50; phot. Zeiss, achr. aa, compens. oc. 6: 

 3-13, 15, 17, 19-21, of form A; 

 14, 16, 18, of form B. 



22, 23. — A small serrated mesamphidisc of form A; magnified 500; phot. Zeiss, H. I. apochr. 2, com- 

 pens. oc. 6: 



22, focussed higher (the uppermost teeth in focus); 23, focussed lower (the centre of the shaft in 

 focus).' 



24-27. — Micramphidiscs of form A; magnified 500; phot. Zeiss, H. I. apochr. 2, compens. oc. 6. 

 28-30. — Three specimens; natural size; phot. Zeiss, anastig. 480/412 mm.: 



28, form B; 



29, 30, form A. 



31-34. — Two micramphidiscs of form A; magnified 2000; u. v. phot. Zeiss, q. monochr. 1.7, q. oc. 10: 

 31-33, a smaller one: 



31, focussed high; 32, focussed intermediate; 33, focussed low; 



34, a larger one. 



35-37. — An abnormal macramphidisc of form A; magnified 500; phot. Zeiss, apochr. 4, compens. oc. 12: 



35, focussed low; 36, focussed intermediate; 37, focussed high. 



