BRYOZOA FROM ZAXZIBAR. 503 



o vice! I are fairly large, though slightly smaller than those 

 of the zocecia. 



The small aviculariiun at the distal corner (figs. 7-9) has short 

 and wide glands which at the lower part are joined together, 

 and no other aviciilarian glands yet seen quite resemble these 

 (text-fig. 80). Avicularian glands occur in Lepralia foliacea Ell. 

 & Sol., L. clivosa Waters, L. margaritlfera, Smittia trispinosa 

 Johnst., Forella plana Hincks, P. acutirostris Smitt, Retepora 

 cellulosa L., and other Reteporm. In all these cases there are also 

 oral glands. The oral glands of S. nivea are hut small with the 

 end cells the larger and darker (PL LXXIII. fig. 16, gl.). 



Text-fig. 80. 



^ ' B 



D 



Avicularian glands of the small avicularia of Scliizoporella nivea. 



A, the two glands separated, X 320. B, the same, X 100. 

 C, glands united, X 320. D, gland, X 820. 



There are 16 tentacles, no pore-chambers, but on the lateral 

 walls there are about eight rosette-plates near the basal wall, also 

 on the distal wall there are about six situated near the base. 



The internal membrane of the zooecium projects in a sac-like 

 manner into the ovicell (fig. 16). This sac is about the width of 

 the zocecium, and is provided with a large number of muscles 

 (fig. 16, sc.) radiating from near the operculum. From a whole 

 preparation it seems that the ovum passes into this sac, which 

 is then ruptured (fig. 16, r) to allow of the passage of the large 

 ovum into the ovicell. I think there is no doubt of my intei-- 

 pretation, although a ruptured membrane has only been seen in 

 one case. The ovarium consists of a number of large ovarian 

 cells. 



Some of the older zocecia are closed by a calcareous layer over 

 the operculum, with a calcareous bar or lamina, extending from 

 side to side (PI. LXX. fig. 3) curving round to the sinus, a position 

 which is fairly constant, not accidental. In older zocecia there is 

 sometimes a calcareous bar straight across the aperture, and there 



