POLYZOA OP WATERWORKS. 457. 



Plate LXIII. 



Statoblasts of various Phj lactolaamata (detailed structure of the annulus not repre- 

 sented). 



The figures were drawn with a Zeiss C objective, and were then reduced two and a 

 halt diameters. The scale represents hundredths of a millimetre. 



Figs. 11-14. IPredericella sultana, showing the variable form and size of the stato- 

 blasts. liatley Waterworks. 

 Figs. 15-17. Plumatella emargmata vnr. miiscosa; floating statoblasts. Torquay 

 Waterworks. 

 Fig. 15. " Ventral" view of a young statoblast. The central capsule is represented 

 by the deeper shadiiig. The line concentric with the outline of the 

 central capsule, and nest inside that line, indicates the extension of 

 the annulus on the " ventral " side. The inner circle represents the 

 edge of the annulus on the " dorsal " side, as seen through the central 

 capsule. 

 Fig. 16. " Ventral " view of an old statoblast. The outline of the central 



capsule is obscured b}' the annulus, and is not seen. 

 Fig. 17. " Dorsal " view of an old statoblast. The annulus covers nearly the 

 whole of this surface of the central capsule. 

 Fig. 18. FlumateJla emarc/iuata var. muscosa. Hamburg Waterworks (from 

 Professor Kraepelin's material). The annulus covers most of the central 

 capsule on this surface of the statoblast. 

 Fig. 19. Fliimatella emarginata var. muscosa. Torquay Waterworks. Sessile 



statoblast, showing the vestigial annulus ; from the unattached surface. 

 Fig. 20. Phimatella emarginata var. muscosa. Hamburg Waterworks (from 

 Professor Kraepelin's material). Sessile statoblast ; from the attached 

 surface. 

 Fig. 21. Plumatella repens. Floating statoblast; from a potid, communicating 



with the River Yare, at Cringieford, near Norwich. 

 Figs. 22-25. Plumatella fungosa var. coralloides. Styche Waterworks (from the 

 pool supplying the system). 

 Fig. 22. Floating statoblast. 



Fig. 23. Sessile statoblast, from the attached surface ; showing the cement- 

 substance by M^liich it is attached to the inner wall of the zooecium. 

 Fig. 24. Sessile statoblast, with well-developed aanulus, the details of which 

 are represented in a small area on the right side of the figure ; from 

 the unattached surface. 

 Fig. 25. Sessile statoblast, with vestigial annulus, w^hich shows remains of the 

 gas-containing cavities (only represented at the upper and left parts 

 of the figure) ; from the unattached surface. 



