BRYOZOA 4 5 



from Capri and Guernsey, Hippothoan, being similar to that of H. hyalina L., while in 

 M. bimucronata from Guernsey the operculum of the central zoœcium is Schiporellidan, like 

 S. auriculata Hass. 



The Antarctic species M. parvipora nov., M. exigua nov., M. proxima nov. hâve some 

 points in common with M. Malusii Aud., and perhaps with a sufficient séries we shall be able 

 to fill up the links between .1/. impressa Aud. and M. Malusii Aud. though, according to those 

 who lay great stress on the shape of the médian pore, they would be placed in différent 

 gênera. The variation in the position and form of the surface pores is very great in this 

 group, and should cause us to hesitate before attaching too much classificatory value to thèse 

 characters. 



From Port Phillip Heads, Victoria there is an allied hyaline form, with a transverse 

 dentate médian pore, and on the front there are small round pores enclosed in an area. This 

 is the species described by Hincks as a variety of M. diadema MacG. ('), form angustipora, but 

 the pore is transverse and in other respects it is quite différent from angustipora, so that we 

 cannot doubt that a mistake has been made. I think it might be called Microporella transversa. 



Habitat. — Exp. Antarct. Belge. 



N° 570, Tangles VIL Lat. 70 23' S.- Long. 82 47' W. ; 480 met. ; +0.8 C. 



N os 619, 683, Tangles VIII. Lat. 70" 00' S.- Long. 8o° 48' W. ; 5oo?met. ; ^0.9 C. 



N° 820, Tangles X. Lat. 70 i5' S.- Long. 84 06' W. ; 56g met. ; +0.8 C. 



Microporella trinervis sp. nov. 



(Pi. 11, fi 8 -. 171 



Zoaiïum adnate. Zoœcia oval, distinct, moderately raised with deep dépressions 

 between the zoœcia. Aperture wide, with the distal end nearly semicircular, and the anterior 

 straight, the lower peristomial lip is raised, and has a slight ,notch. In the middle of the 

 front wall there is a large pore usually elongate, but varying considerably in form, so that 

 in a few cases it might be called semilunar. 



Within the calcareous wall there is a tube, which starts from the peristomial lip and 

 divides close to the médian pore, one branch turning to each side of the zoœcium and ending 

 with a round opening close to the aperture of the next lower zoœcium. Ovicell not much 

 raised with a médian ridge. The spécimens are ail dry, and at présent we cannot follow the 

 significance of the internai tubes, which do not seem to hâve been found in any other Chilo- 

 stomatous Bryozoa, and probably a new genus will hâve to be made, though it has been 

 provisionally placed under Microporella. Only two ovicells were found. The internai tubes 

 can be traced more easily, through having been somewhat stained by the organic matter. 

 There is a further peculiarity in the zoœcia, being evidently connected in the upper part, 

 instead of near the basai part, as usual. 



Habitat. — Exp. Antarct. Belge. 



N° 3gi, Eel trap I. Lat. 71 i5' S.- Long. 87 39' W. ; 436 met. ; —0.2 C. 



(1) Ami. Mag. Nat. Hist., ser. 5, vol. XV, p. 249, pi. VIII, fig. 3a. 



