BRYOZOA FROM ZANZIBAR. 845 
form as a rule there are two zoccia to a series, though there 
may be three, especially near the growing ends, while the larger 
form has three zocecia or occasionally four. A range of inter- 
mediate sizes have been met with. 
The ovicells are anterior, near a bifurcation, or in other 
positions, even often half-way between two bifurcations; large 
pores or pits occur onthe surface. The oceciostome is on one side, 
most frequently by the first zovecium of the second series involved 
(fig. 6), though sometimes it occurs by the third series, but never 
more than one occiostome has been seen on an oviceil, and the 
tubular oceciostome turns over and downwards, resembling in 
position and form the oceciostomes of J. atlantica F., [. concava 
Rss., and /. parasitica Busk. 
The large lateral plates on the ovicell described by me* as 
occurring in Torres Straits and Australian specimens, are not 
seen in those from Zanzibar, though from the localities previously 
mentioned they are very distinct, and are also seen in the 
‘Challenger’ specimens from Tongatabu, and in the British 
Museum specimens from Cape Capricorn, where however they 
are elongate rather than round. There are no frontal ridges on 
the ovicell as described by MacGillivray. The series are about 
0-26 mm. apart, which is much closer together than in any other 
species measured. J. atlantica F. is 0-6-1 mm.; J. australis 
MacG. 0°75 mm.; J. concava Reuss 0°5 mm.; L. pedata Norm. 
0-45 mm.; J. tumida Sm. O17 mm. The zoccial aperture is about 
0-06 mm., whereas in J. atlantica it is 0°15 mm.; in J. milneana 
0-:16-0-2 mm. There are 8 tentacles. 
The ovicell consists of several lobes, there being on both sides 
one between each two series of zocecia, so that in a mature ovicell 
there are usually six such lobes. The embryos are small; the 
mature ones may be 071 mm. across or even a trifle larger, but the 
majority are smaller. There is not much difference from the 
embryos of Hntalophora wasinensis nov., though a little larger, 
but they are smaller than those of Diastopora intricaria Sm., 
0-12 mm. 
Ostroumoff? says the larvee of the Cyclostomata vary in size 
downwards from Hornera which is 0:48 mm., through Tubulipora, 
Frondipora, Lichenopora, to Crisia, which last is only 0-07 mm. 
In sections I have found Hornera lichenoides 0'4 mm. and various 
species of Crisia from 0:07-0°1. The range in the Cheilostomata 
is somewhat similar, as Diplodymoides is 0°08, and Systenopora 
0°37 mm. 
This is no doubt Crisina hochstetteriana Stoliczka t, but the 
* “ Bry. from New South Wales” etc., Ann. Mag. Nat. Hist., ser. 5, vol. xx. 
p- 254, pl. vi. figs. 27,28 (1887). 
+ “Zur Entwickelungsgeschichte der Cyclost. Seebryozoen,” Mitt. Zool. Stat. zu 
Neapel, vol. vii. p. 180 (1887). 
{ “ Foss. Bry. der Grakei Bay bei Auckland,” Novara Expedition, p. 118, pl. xviii. 
fig. 3 (1864). : 
7 57* 
