28 EXPEDITION ANTARCTIQUE BELGE 



The vibracula of F. flagellata lias not been prepared out, as there is only one small 

 spécimen, which is figured as seen in the transparent mount. 



Habitat. — Exp. Antarct. Belge. 



N° 991, Tangles VIII. Lat. 70 00' S.- Long. 8o° 48' W. ; 5oo ? mètres ; +0.9 C. 



Beania magellanica (Busk) 



(PI. VIII, figs. ya-c) 



For svnonyms see Miss Jelly's Catalogue, to which add 



Diachoseris (sic) magellanica Ortmanx. Die japanische Bryozoenfauna lArch. f. Naturgesch., 1890, vol. I, p. 25, 



pi. I. fig. 22 . 

 Beania magellanica Waters, Linn. Soc. Journ. Zoo!., vol. XXVI, p. 16, pi. II, figs. 11-14: Journ. Roy. Micros. 



Soc. ser. 2, vol. V, p. 3, pi. XIV, fig. 4 ; Marion Calvkt, Bryoz. marins de la région 



de Cette [Trav. Inst. Zool. de l'Univ. de 1. . sér. 2. mém. ir. p. z5 : Bryoz. marins de Corse, 



iil.. mém. r2, p. 9. 



The four projections on the dorsal end of the zoeecium are small, but are quite 

 distinct, and although Jullien did not find ihem, in his spécimens from Cape Verde, or 

 Tierra del Fuego, they seem to be pretty gênerai, and though small in the Cape Horn 

 spécimens yet they are indicated. 



According to Ortmann the Japanese spécimen has the edge of the avicularium dentate, 

 but this is not the case in an}- from other localities that hâve corne under my observation. 



Jullien says 2Ô-3o tentacles ; and in my Naples spécimens 26 seems to be the 

 average number : in the spécimen brought b_y the Belgian Expédition I find 23 tentacles. 

 B. quadricorniita H. has 23 tentacles, B. Hyadesi |ull. 20 tentacles. 



It is necessary to refer in some détail to the muscles in the avicularia, as Jullien's 

 figure is not entirely correct in some particulars, and although in my paper on the « Bryozoa 

 from Rapallo (') » correct figures as far as they go were given, it has been advisable to 

 give one with more détail, jullien figures, at the lower or proximal part of the avicularium, 

 thick muscles with isolated fibres, which he calls « muscle en épaulette », but instead of 

 thèse muscles fastened to the base of the mandible, there is a row of isolated muscles in 

 a semicircle round the submandibular part of the avicularium (see pi. VIII, fig. jb), and also 

 «Bryozoa from Rapallo (') », (pi. II, fig. 14). On the upper part they are attached to the 

 front wall, on which there is a semicircular band rather thicker than the rest of the wall ; 

 the lower attachments are to the side walls of the avicularium ( 2 ). 



In my paper, already alluded to, I explained thèse muscles as no doubt contracting 

 the integument behind the mandible, thus helping in the slow opening of the beak ; and 

 the interest of thèse muscles is very great, as we seem to hâve an action hère in the avicu- 

 larium, which must be compared with the muscular contraction in the compensation sac, 

 shown by Harmer to be common in the Cheilostomata. 



(1) Linn. Soc. Journ. Zool., vol. XXVI, p. 16, pi. II, figs. 14, r5. 



(2) In Bugula there are muscles in the proximal part of the avicularium and they are dealt with on page 21 

 under Bugula bicomis. 



