BRYOZOA FROM ZANZIBAR, 851 
the thickening of the “‘Communale Bewegungsorgan ” above and 
below the septa, whereas F. Miiller od ealliadl it a ganglion, 
maintaining that there was a common nervous system “through 
the colony; also Smitt *, in Bugula, called them colonial nervous 
ganglia. We have seen that to these mounds of cells the network 
of plasma threads reaches, and this 1s what has been ealled the 
colonial nervous system and the colonial organ of movement, and 
it was figured by Miller, Reichert, and Nitsche-as a stout, solid 
or tubular body, but Henetiendl there are a number of anastomosing 
and reticulate threads, though with very low powers it may look 
like a band: neither alive nor in stained sections is any such 
solid or tubular band seen. Nitsche’s figures must be looked 
upon as diagrammatic,and Reichert’s, as I have previously stated, 
as though he had Zoobotryon in a pathological condition, and it is 
to be regretted that Hincks copied his figures. Vigelius, Freese, 
and others have correctly understood these plasma threads. 
It is strange that no histological work has been done on 
Zoobotryon, as it is eminently suitable for elucidating many 
interesting and important points of cell-structure, etc. 
The name rosette-plate was given supposing that there was a 
rosette of pores, whereas there is really a rosette of cells. 
Loc. Add: Florida (Osb.); Chuaka Bay, Zanzibar, 2 fath. (509), 
collected by Crossland. 
BowERBANKIA PuSTULOSA (Ellis & Solander). 
Sertularia pustulosa Ellis & Solander, ‘‘ Nat. Hist. of many 
curious and uncommon Zoophytes,” p. 54 (17&6). 
Bowerbankia pustulosa Hincks, Brit. Mar. Poly. p. 92 
pl. Ixxvi. figs. 1, 5 (1880); Calvet, “ Bry. Ectoproctes,” pl. vi. fig. 13, 
pl. vii. fies’ 4- 8, Ole WIM, Teva, AN Golly axe ibe, Wey yolks oa, figs. 18, is 
pl. xu. figs, 15- i, jolle, sani figs. 11, 14 (1900). 
The descriptions and determinations of Lowerbankia are so 
uncertain that there seems little object in giving a full list of 
synonyms. This species has been mistaken 7 for Valkeria uva L. 
and 5. imbricata Adams. 
Loc. British; Mediterranean ; Chuaka, Zanzibar Channel, shore 
(523), collected by Crossland. 
MIMOSELLA BIGEMINATA, Sp. n. (PI. IIT. figs. 1-3.) 
The zoarium eonsists of unbranched stems (about 0°3 mm. 
diameter) rising from a spreading stolon (about 0°15 mm.). The 
first internode of the stem is long (say about 1:65 mm.) followed 
by one about 0-4 mm., and then the remaining ones are shorter, 
say 0°35 mm. There may be as many as 50 internodes in a stem. 
In the lower internodes there is only a pair of opposite zocecia 
close to the distal end, but after the second or third internode there 
is a second pair placed rather to the side and lower down but 
* Hafs-Bry. Utveck. Ofv. Stockh. Akad. xxii. pl. vi. fig. 7 (1865). 
+ See Waters, “ Mar. Biol. of the Sudanese Red Sea, Bryozoa,’ Journ. Linn. Soc., 
Zool. vol. xxxi. pp. 249, 250 (1910). 
