PLATE X. 



Fig. ] . — Ginachyra vertex Lendenfeld, nafc. size, p. 9. 



Fi&. 2. — Vertical section of a porocalyx (x 10). 



Pig. 3. — Vertical section of an oscule ( x 10). 



Fig. 4. — Vertical section of cortex ( x 25). 



Fig. 5. — Flagellated chambers, apopyles opening into beginning exhalant canal (x 160). 



Fig. 6. — Collar cells ( x 1600). — The section shows the cut edges of the concrescent collars of the collar 

 cells ; the diffused coloration beneath these cut edges apparently represents SoUas's membrane torn 

 down in the course of section cutting. The material from which the section was cut was deep black 

 from the effects of osmic acid, and was not good from a histological point of view. 



Fig. 7. — Large somal oxea (x 100). 



Fig. 8. — Choanovsomal oxea ( x 100). 



Fig. 9. — Anatriaene with bend in cladi (x 100). 



Fig. 10. — Anatriaene with uniformly curved cladi (x 100). 



Figs. 11, 12. — Protriaenes. 



Fig. 13. — Trichodal protriaene (x 100). 



Pig. 14.— Sigmata (x 700) ; 14a, the same (x 1400). 



P'iG. 15. — Ginachyra vertex var. monticularis, n. var., nat. size, p. 11. 



Fig. 16. — Oscular chimney of the same (x 10). 



