ANTARCTIC BRYOZOA — ROGICK 303 



elevated peristome. The mural rims are depressed or inconspicuous. 

 Internally, the compensation sac occupies most of the frontal surface. 

 On the basal surface, brownish membranous tubes connect neighboring 

 zooecia (pi. 31,K), from 2 to 5 penetrating each wall of the hexagonal 

 zoid. 



Avicularia: No avicularia are present in the small amount of 

 young material at my disposal. However, the peristome does show 

 a deeply colored reddish triangular process between the lyrula and the 

 external peristomial notch (pi. 31, A,C,F-I). This process is similar, 

 except for its intense color and its sharpness, to the broader colorless 

 ledge which supports the oral avicularia of Smittina ordinata and 

 Smittina canui. Moreover, in one zooecium (pi. 31,1) it appears to 

 connect with a presumable or potential avicularial chamber. How- 

 ever, its true nature must await examination of more material. 



Orifice: The elevated orifice is frontal and surrounded by a thin 

 collarlike peristome which is notched medially. The peristomial 

 distal wall is distinct in the youngest zoids but in older zoids the next 

 distal zooecium fuses with it. 



The primary orifice is set so deeply inside the peristome that its 

 lyrula is not visible easily from the outside. Consequently, one could 

 very readily mistake this species for a Schizoporella. The primary 

 orifice is wider than long, broadly arched distally, more contracted 

 and shallower proxunally. The lyrula and its two narrow bordering 

 sinuses occupy this narrower proximal part. A pointed, deeply 

 colored reddish process protrudes in front of and above the lyrula 

 (pi. 31,A,C,H,I). Its point is close to the notch and visible from 

 the outside (frontally). Its role is not clear at present. 



There was not enough material for an adequate study of the oper- 

 culum other than to measure it. 



The chief feature which determined the placement of this species 

 into the genus Smittinella is the deep channel which slopes downward 

 from the secondary orifice to the primary orifice, parallel with the 

 peristomial notch. Its side walls are the two ledges that reinforce 

 the sides of the notch (pi. 31,B,C,F). 



OvicELLs: The only ovicell found is pictured in plate 31,D,H. It 

 is hyperstomial, tipped slightly back and beaded. Its single frontal 

 pore is membrane-covered and has decorated edges, thus differing 

 slightly from those of Smittina ordinata. Also, the peristome gives 

 an indication of possibly encroaching upon the frontal surface of the 

 ovicell. 



Distribution: This species is represented by several small colonies, 

 including the holotype (USNM 11309), which encrusted a rock from 

 Station 184 in Marguerite Bay. 



350640—56 7 



