BUYOZOA FUOM ZANZIBAR. 501 



structure is found in connection with them (fig. 16). On the 

 inner side (towards the older zooecium) there is a large saucer- 

 like portion with a fleshy club-like projection on the other. The 

 wall of the zooecium and the rosette-plate passes between the two. 



From the tissue round one of these rosette-plates the pol3'pides 

 of the growing parts start, but many of the polypides have the 

 retractor muscles always attached to the lateral wall. The ten- 

 tacular part of the bud seems to be growing in one distal corner 

 while the gut parts are growing in the other, and in the matui-e 

 polypide a long tube connects the two (fig. 1 2). This narrow tube 

 connecting the two parts is a character of the mature polypide, 

 and is somewhat like that of the oesophageal tube of the 

 Ctenostomata. 



There are very few secondary buds to be seen (as the zooecia 

 nearly all contain perfect polypides) ; they, however, arise from 

 tissue on the membrane crossing the opercidum. 



There are about 25 tentacles, four of which near the base are 

 larger and broader than the others. 



In other species of Steganoporella there is also considerable 

 variation in the teeth of tlie opercula ; for example, in a specimen 

 of *S'. buskii H. from Algoa Bay, South Africa, in the British 

 Museum, there is a B operculum without any teeth whatever, 

 whereas the other opercula have small teeth. 



Steganoporella is not yet known before late Tertiary, whereas 

 Thalcnnioporella is much older. 



Log. Brazil ; Jamaica ; St. Vincent ; Florida ; China Seas ; 

 Singapore ; Philippine Islands ; Trincomalee ; Amirante Isl., 20- 

 25 fath. {Thornely). Wasin, Brit. East Africa, 10 fath. (500) 

 (520) ; Chuaka, Zanzibar Channel, 2 fath. (508), collected by 

 Crossland. 



Fossil. Australian Tertiaries. 



Cribrilina radiata Moll. 



Log. Cosmopolitan. Has Osowamembe, Zanzibar Channel, 

 10 fath., on Adeonella platalea, collected by Crossland. 



HiPPOTHOA DiVARiCATA Lamouroux. 



Log. Wasin, Brit. East Africa, 10 fath. (520), on shell, collected 

 by Crossland. 



HiPPOTHOA DiSTANS MacGillivray. 



For synonyms see Waters, " Bryozoa," Besultats du Voyage du 

 S.Y. Belgica, p. 54 & pi. iii. fig. 8 (1904). 



Log. Wasin, Bi-it. East Africa, 10 fath. (520), on shell, collected 

 by Crossland. 



SCHIZOPORELLA UNICORNIS Johnstou, 



Waters, " Bryozoa of the Sudanese Red Sea," Journ. Linn. 

 Soc, Zool. vol. xxxi. p. 143, pi. xii. figs. 12, 13 (1909). 



Some pieces are either one or two lavered, and here again I 



