ANTARCTIC BRYOZOA — ROGICK 263 



the corner of the orifice so as not to show from the outside. Two 

 external avicularia, each set obhquely below the lower corner of the 

 orifice, with beaks pointing diagonally upward and outward. Mucros 

 absent. Primary orifice crescentic. Secondary orifice varies in shape 

 from an inverted triangle to a more transverse slit, depending upon 

 degree of overgrowth. Oral ledge, gently arched, forms the proximal 

 border of the primary orifice and is nearly parallel with the frontal 

 plane. 



The species is named in honor of the writer's mother, whose maiden 

 name was Nj ego van. 



Zoarium: The amount of material collected was four fair-sized 

 pieces and some smaller fragments. Figures a and b of plate 15 

 represent the larger pieces. One was 33 mm. long. The zoarium is 

 ivory-colored, heavily calcified, with chitinous rootlets sprouting from 

 some of the basal zoids. An internode may have 2 to 18 rows of zoids 

 along its length and 12 to 25 rows of zoids across its width, on one 

 face. These counts were made on the broader blades and not on the 

 narrow base. The colony sm'face is punctured by numerous chan- 

 neled pores (pis. 15,C,D,H; 16,1). The zooecial orifices are visible to 

 the naked eye. 



Zooecia: Externally, zooecial boundaries are not distinct (pis. 

 15, C; 16,A); but internally and in cross section they are (pis. 15,D,H; 

 16, H). Approximate zooecial length, by external measurement from 

 one orifice to the next orifice in line, 1.075-1.523 mm. (average 1.315 

 mm.), comparing favorably with that of a single zoid measured from 

 the inside, 1.368 mm. Zooecial width, from inside measurements, 

 0.360-0.605 mm. (average 0.431 mm.). 



Frontal walls are very thick, lateral and back walls are thin. As 

 seen from the mner surface zooecia are shaped like inverted flasks. 

 Their bulging upperpart is devoid of pores except at the sides; the 

 narrow proximal part has a number of pores (pis. 15,D,E; 16,1). 

 These pores open into some of the frontal channels. The back wall 

 of the zooecium is flat (pis. 15,H; 16,H). The side wall has a few 

 elliptical rosette plates near its midline (pi. 15,G,H). These ma}^ 

 have up to 14 pores. Pore chamber length is 0.137-0.202 mm. 

 (average 0.164 mm.) long and 0.086-0.137 mm. (average 0.111 mm.) 

 wide (only four readings). In addition to these pore chambers, or 

 rosette plates, the side wall also has a number of single pores, arranged 

 roughly in two or three rows along the edge nearest the frontal wall 

 (pi. 15,G,H). The end wall has the usual sieve plate and two cal- 

 careous processes, the latter a bit more elaborate than in the other 

 species (pis. 15,G; 16,H). 



In the node region the zooecial cavities are very greatly reduced by 

 the encroachment of the walls (pi. 16H,). 



