ANTARCTIC BRYOZOA — ROGICK 231 



nonfertile and more curved in ovicelled zooecia. There is considerably 

 more length to each zooecium than appears at the surface because the 

 proximal part of each zoid is narrowed and considerably extended to 

 fit neatly between and beneath the side walls of the next proximal row 

 of zooecia. Zooecial measurements are as follows: length of external 

 (surface) face 0.490 to 0.662 mm. (average 0.619 mm.); width of ex- 

 ternal surface face 0.230 to 0.317 mm. (average 0,281 mm.); genuine 

 over-all, internal and external length of zooecia 0.835 to 1.181 mm. 

 (average 1.094 mm.). 



The zooecial frontal surface, a cryptocyst, is pebbled or covered 

 with small, well spaced bumps. The cryptocyst is somewhat pan- 

 shaped, the central frontal area depressed or flattened while the side 

 walls arise upward and outward at an angle (pi. 6,C). The walls also 

 are pebbled. Two conspicuous, beaded ridges, curvedlike parentheses, 

 arise from the frontal (cr in pi. 6,B), They begin in the arched or 

 gabled distal walls, at each side and above the zooecial orifice, then 

 curve convexly along the frontal surface, near each lateral wall, but 

 do not meet proximally. These cryptocyst ridges are present on the 

 frontal of this species as well as the inconspicuous delicate smaller 

 parenthesis-shaped chitinous rods or trabeculae which Busk (1884) 

 cites as occurring at the two sides of the operculum in some other 

 species (pi. 5,H). 



Zooecial orifice: The orifice through which the tentacles are 

 extruded and which is closed by an operculum is of typical Cellaria 

 form, arched in a semicircle distally, broadly and slightly concave 

 proximally, with two teeth or condyles, one in each corner (pi. 5,H). 

 The upper lip or distal arch presents a hooded and beaded appear- 

 ance (pi. 6,L). The lower lip is smooth and protruded as in a pout. 

 The whole orifice is raised above the cryptocyst frontal area like a 

 dormer window (pi. 6,D). The arched distal walls of the zoid meet 

 rooflike above the projecting orifice (pi. 6,H). The orifice is closed 

 by a smooth chitinous operculum which is lightly reinforced around 

 the edge (op in pi. 6,C). Orifice length varies from 0.038 to 0.054 

 mm. (average 0.048 mm.) in midline and the width ranges from 

 0.115 to 0.130 mm. (average 0.121 mm.). Its total, over-all, boxed- 

 in length varies from 0.058 to 0.072 mm. (average 0.063 mm.). 



OviCELLS. The ovicells (ov in pi. 6,B) are endotoichal with distal 

 end slightly truncate. They form low mounds, longer than wide, 

 around the branch (pi. 6,A). Their length is from 0.187 to 0.259 

 mm. (average 0.232 mm.). Their width is from 0.187 to 0.216 mm. 

 (average 0.197 mm.). They are buried under the flaring walls of 

 the three adjacent zoids (the two lateral and the parent-proximal 

 zoids). These walls meet in a thin salient line, like an inverted 



