BRYOZOA 3i 



the muscles bulged out, and was very transparent, showing the muscles through the walls 

 (figs. Sc-d). 



Habitat. — Exp. Antarct. Belge. 



N° 343, Tangles IV. Lat. 71° 18' S.- Long. 88° 02' W. ; 435 met. ; — o.3 C. 



N° 1012, Tangles VIL Lat. 70 23' S.- Long. 82 c 47' W. ; 480 met. ; +0.8 C. 



Membranipora irregularis d'Orbigny, and Smitt (non Hag.) 



Membranipora irregularis d'Orbigny, Voyage dans l'Amérique méridionale, vol. V, pt. 4, p. 17, pi. VIII, 

 figs. 5-6; Smitt, Floridan Bryozoa, pt. II. p. 8, pi. II, fig. 63; ? Busk, Quart. Journ. M ter. Se, vol. I, 

 1861, n. s., p. 77, pi. XXXIII, fig. 3. 



This species lias the zoœcia about the same size as the larger form of M. incrustons 

 Waters, but there are no avicularia, and the ovicell is wide, cap-like. From d'Orbigny's 

 figures it is difficult to be sure what he had before him, but Smitt has since refigured spéci- 

 mens which he considered were M. irregularis. I did not see anv M. irregularis in the Muséum 

 d'histoire naturelle in Paris. 



In the spécimen from 619, growing on stones, the polypides can be seen. 



Habitat. — Aladeira ? (Busk) ; Florida (Smitt) ; Falkland Island (d'Orb.). 



Exp. Antarct. Belge. 



N os 619, 683 on stones, Tangles VIII. Lat. 70° 00' S.- Long. 8o° 48' W. ; 5oo ? mètres ; 

 +0.9 C. 



Membranipora incrustans Waters 



(PI. II, figs. i5a. h. c) 



Membranipora incrustans Waters, On Membraniporidas. [Linn. Soc. Journ. Zoo!., vol. XXVI. p. 6S6. pi. XLVII, 



fig- i3.) 

 Membranipora crassimarginata var. incrustans Busk (pars), Zool. Chall. Exp., vol. X, pt. XXX, p. 63. 

 Membranipora Dumerilii (Aud.). Waters, Supp. Rep. Zool. Chall. Exp., vol. XXXI, pt. LXXIX, p. 12. 

 Membranipora coronata Julliex (non Hincks), Bryozoaires. Mission du Cap Horn, p. 76. 



Spécimens from 570 and 596 hâve zoœcia about the same size as those of the Challenger 

 spécimens, but the avicularium is rather larger and the avicularian chamber is often more 

 raised. This is larger than M. levata Hincks. A spécimen from 392 is however still larger 

 than the others having zoœcia about i mm long instead of about o.6 mm -o.7 mm . There are several 

 species of Membranipora with oval zoœcia and an avicularium at the distal end, and this group 

 is a difficult one on account of the few characters available. 



I saw several spécimens of this in Paris in the material collected by the Cape Horn 

 Expédition and the short avicularium distinguisb.es it from the M. coronata of Hincks, which 

 has a vibraculum. Julliex evidëntly intended to make a new genus for Membranipora with 

 a vibraculum above the zoœcium, but this is not a sufficient reason for a fresh genus, as we 

 know other gênera having either avicularia or vibracula. 



