244 MARINE BIOLOGY OF THE SUDANESE RED SBA. 
Dedalea mauritiana, Quoy & Gaimard, Voyage de I’ Uranie, vol. iv. p. 229, pl. 26. figs. 1, 2. 
Voyage de l’Astrolabe, p. 952, pl. xxvi. figs. 1-7. 
Bowerbankia biserialis, Hincks, “ Polyzoa of the Adriatic,” Ann. Mae. Nat. Hist. ser 5, 
vol. xix. (1887) p. 309, pl. 9. fig. 6. 
Vesicularia bilateralis, MacG. Trans. Roy. Soc. South Australia, p. 30, pl. 2. fig. 4 (1889). 
Description of a Ctenostomatous Polyzoa, J. D. Macdonald, Proc. Roy. Soc. vol. viii. 
(1857) p. 383. 
This has also been described in botanical works under various names as 
Ulva intricata, Clemente; Valonia intricata, Agh. ; Ascothamnion intricata, 
Kiitz. ; A. Trinitatis, Sond. 
Further particulars are given by Reichert and by Miss Jelly in her 
Catalogue. 
This may be said to be Ehrenberg’s type of Bryozoa, and was correctly 
and fully described by him. He saw the setose collar, as it has been calied, 
also the gizzard, and gave the number of tentacles as eight. 
Round this species there have been discussions not only as to whether it 
was a plant or an animal, but also as to whether the mesenchym threads were 
a colonial nervous system or a colonial organ of movement. When Hincks 
met with this classical genus he did not recognise it, and called it Bower- 
bankia biserialis, Hincks ; however, thereby he unconsciously showed the 
identity of Bowerbankia with Zoobotryon, so that by the laws of nomenclature 
we are forced to drop the well-known genus and replace it by Zoobotryon, 
which will not be reverting to a disused name, but merely showing the 
identity of what kave been understood as two genera. It is true that Hincks 
only speaks of two opposite branches at a joint, and in younger branches of 
Z. pellucidum this is often the case ; besides Hincks’s fig. 6 a, pl. 9, so far as 
I can understand it, shows two thick branches and a short terminal one, so that 
although the description does not correspond in this one particular, I think 
we may feel satisfied that bzserialis is a synonym. 
Ehrenberg first spoke of the “ collare setosum,” and Busk subsequently 
made the setose collar a distinctive character of his suborder Ctenostomata. 
In Zoobotryon there is no real setose collar, but the thin membrane is ridged 
and folded, and the lines of the fold give the appearance of separate setee, 
but with higher powers it is clear that the membrane is continuous. The 
structure is correctly shown by Reichert, pl. 1. fig. 3, and by Ehlers for 
Hypophorella expansa, pl. 2. fig. 10, and some other term would have been 
more satisfactory, but neither “fringe” (incks) nor ‘‘ bristles” is any 
better. In consequence of seeing that this collar is not divided in Zoobotryon 
pellucidum a large number of Ctenostomata have been examined without ever 
finding true setee on the collar. At the time this examination was made it 
had escaped me that Jullien * had shown how this collar simulates by its 
folds a bundle of setee. Busk, in his ‘ Challenger’ Report, p. 37, says that 
* Mission du Cap Horn, p. 15. 
