232 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 105 



Y or T over the ovicell front (mr in pi. 6,B)- A transverse banana- 

 shaped ooeciopore (pi. 6,B) opens mto the ovicell. The ooeciopore 

 length from 0.014 to 0.029 mm. (average 0.023 mm.); width from 

 0.086 to 0.101 mm. (average 0.097 mm.). There is a sizable strip 

 of cryptocyst between the ooeciopore and the zooecial orifice. The 

 zooecial walls which meet over the front of the ovicell are beaded or 

 pebbled. There are no pores in the frontal of the zoids or in the 

 ovicell frontal. 



Avicularia: The avicularia are few, vicarious, smaller than the 

 regular zoids (autozoids), and placed longitudinally above the distal 

 arch of a zooecium between the side walls of the two zooecia of the 

 next series (pi. 6,D-F). Their shape varies somewhat from spindle 

 to pentagonal, with length greater than width. Their over-all dimen- 

 sions are: length from 0.187 to 0.317 mm. (average 0.236 mm.); 

 width 0.101 to 0.173 mm. (average 0.127 mm.). They are bordered 

 by a salient line. The avicularial beak is acutely triangular and 

 raised at the distal tip. Its opening or opesia is pointed distally 

 and is set off from the proximal hemispherical space on each side by 

 a toothlike ledge. The mandible is an elongate triangle (pi. 6,K). 

 The avicularium does not replace a zooecium in a series but is inserted 

 between them (pi. 6,D). The proximal avicularial surface is beaded 

 or pebbled (pi. 6,E). 



Radicles: Radicles are transparent, yellow chitinous tubes arising 

 either freely from the front of the zoids or located in a tangled mass 

 at the joints. The former are long, slender, single or double tubules 

 which spring out from the front of the zooecium, through the crypto- 

 cyst, below the zooecial orifice and pass downward to form rootlets 

 or holdfasts near the base of the colony (pi. 6,I,J). They begin to 

 branch tortuously a short distance from the zoid front. The second 

 group of radicles, those located at the joints or nodes, form a compact 

 tangled yellow mass at the point of dichotomous bifurcation of a 

 branch. They sprout from the zooecia at the node (pi. 5,1). 



Types: Holotype, USNM 11210; paratypes, USNM 11211. 



Ecology: Other forms may grow on this Cellaria — namely, Fora- 

 minifera and Bryozoa like Cellepora and Hippothoa distans. Its root- 

 lets or radicles may adhere to other Bryozoa. Cellaria moniliorata 

 was collected at Antarctic Stations 104 and 115. The amount of 

 material collected was a small vial containing numerous colony frag- 

 ments. 



Cellaria vitrimuralis, new species 



Plates 4; 5,A-E 



Diagnosis: Colony erect, calcareous, fragile but more robust than 

 Cellaria moniliorata, articulated, composed of slender internodes which 



