464 MR. A. W. WATERS ON 



in A. recta from Rapallo* and Naples in the Mediterranean, and 

 in the ' Belgica ' Antarctic material. Miss Robertson describes 

 ovicells on the front, some distance down, but was in doubt as to 

 whether the species was a true A. anguina. Whether she really 

 had another species before her or not must be left uncertain, but 

 certainly the front position as drawn by lier is a very strange and 

 unexpected one. 



Miss Robertson has confirmed what I wrote about the ovaria 

 occurring in the creeping part, and this seems to be the usual 

 place ; however, in the present specimens I do not find that the 

 polypide extends far into this part, as it sometimes does in ^. recta 

 and as Miss Robertson describes and figui-es in A. anguina. 



Smitt, Waters, Jullien, and Robertson have all shown that the 

 polypide etc. does not entirely live in the tubular prolongation ; 

 but Jullien, although appi-eciating the fact, called this part the 

 peristome or peristomia. Surely the peristome is something 

 beyond the operculum and is the part where the polypide is only 

 to be seen when extended ; so that this term applied to Aetea is 

 most unfortunate and misleading. This tubular prolongation 

 has been called the neck, and the terminal portion the spoon, but 

 no satisfactory name has been given to the creeping portion, which 

 is only a part of the zooecium. There are 12 tentacles. 



The diaphragm does not make an infold when retracted, like 

 most of the Cheilostomata ; and the appearance of setae, which 

 has frequently been alluded to, must be caused by a partial 

 extrusion of the diaphragm. In some respects Aetea appi-oaches 

 the Ctenostome Cylindroecmm, but no Ctenostome has an external 

 ovicell . 



I do not altogether understand what Levinsen t says regarding 

 the ovicells of this species ; for though the wall of the ovicell is so 

 thin that the embryo can readily be seen, yet decalcified pre- 

 parations and sections have been studied. If Levinsen means to 

 suggest that the sacs containing the ova and embryos are only 

 accidentally at the termination and might adhere in any position, 

 then this is not the case, as I have now seen a large number, perhaps 

 hundreds, always in exactly the same position, and see no reason 

 why we should not speak of them as ovicells. One section shows 

 the zonecial wall bulging out and the ovum partly in this portion, 

 which is the commencement of the ovicell J. 



Log. Arctic ; Atlantic ; Mediterranean ; Gulf of Manaar ; 

 Zanzibar [Hinchs) ; S. Africa ; Australia ; ISTeAv Zealand, Tas- 

 mania ; Pacific ? (Robertson) ; Tristan da Cunha (' Challenger '), 

 Wasin, Brit. E. Africa, 10 fath. (500 §), collected by Crossland. 

 Fossil. Upper Tert. Italy (N^eviani), Helvetian of Egypt {Canu). 



* " Biyozoa from Rapnllo," Journ. Linn. Soc, Zool. vol. xxvi. p. 5, pi. i. figs. 1-5 

 (1896). 



t Morph. & Syst. Studies on the Clieil. Bry. p. 93 (1909). 



X Since tlie above was written, Prof. R. C. Osburn has confirmed the existence of 

 ovicells in the position described, having found numerous such ovicells in specimens 

 from Fish Hawk Station : see " Bvyozoa of the Wood's Hole Region," Bull, of the 

 Bureau of Fisheries, vol. xxx. Document No. 760, p. 220 (1912). 



§ These and similar numbers are Crossland's registration numbers. 



