BRYOZOA FROM ZANZIBAR. 519 



tube. There are a few large spatulate avicularia at one of the 

 distal corners, and these also have a distinct cross-bar. Speci- 

 mens of M. vultur in Miss Thornely's collection show the mandible 

 serrate. 



There is a fairly broad lyrula and two cardellse, and the lyrula 

 is formed before the front wall is complete. Only one ovicell has 

 been seen, and that is partly broken, but it is broad and minutely 

 perforated. 



Oil the dorsal surface there are perforated spaces, no doubt for 

 radicles, but there are usually sevei'al small ones instead of one 

 large one as in Lepralia dorsiporosa B. 



Similar ovicells with minute perforations occur in Petralia un- 

 data MacG., P. japonica Busk, F. vidtur Hincks, P. ellet-ii MacG., 

 P. (M'uci'onella) magnifica Busk, P. (^Escharella) bisiimata Smitt 

 (no7i Busk), P. thenardii Aud., P. {M.) porosa Hincks, P. {M.) 

 castanea Busk, L. crassa Thornely; and these Levinsen would 

 place in his family Petraliidse, and thus it would seem as though 

 a genus can be separated based largely on the ovicell. In the 

 species of this group which it has been possible to examine, there 

 are a large number of tentacles, viz., Petralia undata MacG., 

 about 26 ; P. japonica B., about 25 ; P. castanea B., about 23 ; 

 P. vidtur var. armata, nov., about 25 ; P. chuahensis , nov., 

 about 25. 



There seem to be two tentacles larger than the rest (figs. 1 5-17), 

 and these, instead of being triangular, have the inner surface 

 nearly straight, with a number of long nuclei. On this inner 

 surface there are cilia, but unfortunately the condition does not 

 admit of exact study of this point. These two larger tentacles 

 occur in all the species examined of the group, and larger tentacles 

 occur in other groups to which I have previously alluded. These 

 large tentacles are most marked near to the base of the tentacles 

 when they are commencing to divide, whereas nearer to the ends 

 there is but little difference. 



Log. Ohuaka, Zanzibar, 3 fath., 29.3.1901 (506), collected by 

 Crossland. 



? ESCHAROIDES OCCLUSA Busk. 



See "i. Lepralia occlusa Waters, " Mar. Biol, of the Sudanese Red 

 Sea," Journ. Linn. Soc, Zool, vol. xxxi. p. 152, pi. xiii. fig. 15, 

 pi. xiv, figs. 1-9, 13 (1909). 



The distal and lateral walls have numerous scattered uniporous 

 rosette-plates, especially near the inner borders. At the side of 

 the zoarium there are often two large spatulate opposite avicu- 

 laria, whereas in Adeonella the avicularia are usually on a median 

 line. 



Levinsen would put this under Myriozoidea, but I hardly think 

 he can have had sufiicient material before him when writing about 

 the family, and that is often our dilficulty in considering classi- 

 fication. 



