RRYOZOA FROM ZANZIBAR, 529 



Diplodidymia conipllcata Rss. (text-fig. 79, p. 491) may throw 

 some light upon the growth. 



Blind cells, that is cells without an oral aperture, are very- 

 frequent throughout the family, and sometimes the central or 

 stalk portion is composed of such cells, A few have a closure 

 somewhat like those of the Cyclostomata, but not entirely so, as 

 a membrane from below the operculum spreads to the front to 

 make the funnel-like closure. Membranous closures are also 

 occasionally found, and these may be perforated. These closures 

 with tubuli occur in Adeonella conlorta Mich,, and I have found 

 them in Lepralia syringopora Rss., one of the Adeonidje. 



The goncecia in Adeonidse, when distinguishable, frequently 

 are situated near the border, but in one species they are all 

 situated on the median line, while in another they are in groups 

 in various places, distinguishable by the naked eye. 



In my recent paper dealing with Adeonidse I alluded (p. 496) 

 to the occlusor muscles being, as a rule, single in triangular 

 mandibles, whereas the semicircular mandibles usually have two 

 tendons. A slightly different statement would have been better, 

 as I was aware of some exceptions, and since writing I have come 

 upon more — in fact in Cellepora and Holoporella many of the 

 triangular mandibles have two tendons, but in Flustra, Membrani- 

 pora, Retepora, and Grihilina, etc., and in most genera the rule 

 seems to be, only one tendon to the triangular mandibles. Some 

 of the exceptions may be in semicircular avicularia modified 

 into triangular ones. I have not got a record on this point of all 

 the mandibles prepared, and must make further examination. 



Adeonella platalea Busk. (PI. LXXIII, figs. 3-5, 8 k 

 text-fig. 82.) 



Eschara platcdea Busk, Brit. Mus. Oat. Mar. Pol. p. 90, pl. cv. 

 figs. 1, 2 3, pl. cviii. fig. 4 {fide Busk) (1854); MacGilHvray, 

 Prod. Zool. Vict, dec, v. p. 41, pl, xlviii, fig, 4 (1880), 



Eschar a hexagonalis Haswell, Proc. Linn. Soc. N. S.Wales, vol. v. 

 p. 41, pl. iii. figs. 1, 2(1881). 



Adeonella platalea Busk, Zool. Chall, Rep, vol, x, pt, xxx, 

 p. 184, pl. xxi. figs. 4, 4 a (fe fig, 50 (1884) ; Meissner, M., "Liste 

 der von Herrn Prof. Semon bei Amboina und Thursday Island 

 gesammelten Bryozoen," Jenaische Denk. vol. viii. p. 731 (1902); 

 Waters, " A Structure in ^cZeo?^eZ/a {Laininopora^ contorta Mich.," 

 Ann. Mag. Nat. Hist. ser. 8, vol. ix. p. 489 (1912), 



Escharinella cecilleana d'Orb, Pal. Frang, vol. v, p. 207 (1850) ; 

 and see Waters, Ann, Mag, Nat. Hist, ser. 7, vol, xv, p, 5 

 (1905), 



I have not had the opportunity of re-examining the E, cecilleana 

 d'Orb. since this collection was taken in hand, but the name 

 cecilleana cannot be retained, as the description was insufficient. 



The ovicellular sac (fig. 3) is formed near the distal end 

 and ultimately fills up nearly the whole of the zocecium, but 



