. ANTARCTIC BRYOZOA — ROGICK 255 



In the succeeding discussion of species the maximum-minimum- 

 average measurements for particular parts or structures are based on 

 1 10 readings unless otherwise specified. 



Cellarinella margueritae, new species 



] Plate 12 



Diagnosis: Zoaria narrow, flattened, ribbonlike bilaminate strips, 

 with some zoids opening out along the edges also. Two mucros, one 

 in front of each proximal corner of the orifice. External avicularium 

 along median side of one of the mucros, arranged at an approximate 



' right angle to the longitudinal axis of the zoid. Internal avicularium 



I slants obliquely distally. External avicularial mandible wider than 

 long. Mandibles of both triangular and with a hooked tip. Orifice 

 hemispherical distally, only slightly curved upward proximally because 

 of the inner frontal oral ledge. 



O. margueritae is so named because it was collected at Marguerite 

 Bay, Antarctica. It difi^ers from C. nodulata, depicted in Waters' 

 monograph (1904, pi. 8, fig. 6a), in the number and position of mucros 

 and the location of the external avicularium. In C. nodulata the 



• mucro is central or median in location and the avicularium is decidedly 

 lateral in position, at the very corner of the orifice, and directed 



' obliquely upward and outward. In C. margueritae the mucros are 

 two in niunber and lateral in position. The external avicularium 

 extends from the midline outward, transversely. 



'■ Zoarium: 16 ivory-colored, calcareous, hard fragments of this 

 species were found. The longest is 47 mm. Width is up to 4 mm. in 

 some. Thickness of blade is about 2 mm. Judging from the presence 

 or absence of the thin parchmentlike membranous covering over the 

 colony some of the colonies were living, some dead, at the time of 

 collection. The zoarium consists of a bilaminate, nodulated, flattened, 

 narrow blade roughly resembling a tapeworm (pi. 12,A). Branching 

 is sparse and dichotomous. Nodes and internodes differ in external 

 appearance only in that the nodes are a bit more pinched-in and lack 

 orifices, thus looking less pitted than the internodes. The nodes are 

 not jointed or flexible but are of the same calcareous construction as 

 the internodes. The internodes are from 4 to 8 mm. long. There 

 are from 3 to 1 1 vertical rows of zoids in an internode. The number 

 of zoids in a horizontal row across one face of an internode ranges 

 from 5 to 10. The slightly prickly feel of the colony surface is due to 

 the projecting mucros, usually two per zoid. 



Zooecia: The only external indication of a zooecium is the orifice 

 with its neighboring structures, the two mucros and the external 

 avicularium. All other parts of the zooecium and its neighbors are 



