ANTARCTIC BRYOZOA — ROGICK 307 



both in general size. The length and width of the zooecia, ovicell, and 

 operculum of the Antarctic specimens are about double the corre- 

 sponding dimensions of Brown's sample. Brown's (1952, p. 330) 

 measm-ements, in millimeters, are: zooecial length, 0.52-0.60; zooecial 

 width, 0.29-0.31; orifice length, 0.17-0.19; orifice width, 0.15-0.16. 

 Marcus does not give measurements but does include scales on the 

 plates, and by use of these scales his material seems to have the follow- 

 ing approximate millimeter measurements: zooecial length, 0.38-0.50 

 zooecial width, 0.23-0.35; ovicell length, 0.18-0.20; ovicell width, 0.23 

 operculum length, 0.08; operculum width, 0.11; lyrula length, 0.04 

 hTula width, 0.06; mandible 0.04 by 0.08. Therefore, the Antarctic 

 specimens would appear to be about double the zooecial, ovicell, and 

 operculum figures of Marcus but approach closely his figures in the 

 size of the mandible and lyrula. In both the Brazilian (Marcus') and 

 the Antarctic specimens the median denticle or process is lacking in 

 the cross bar (pivot) of the avicularium, but whether the denticle is an 

 important character is uncertain. The significant difference between 

 S. evelinae and Levinsen's S. acaroensis is in the size and orientation of 

 the avicularium and the nature of the distal orifice border. Levinsen 

 (1909, pi. 18, fig. 12) shows a very large avicularium apparently placed 

 flat on the zooecial front, somewhat as in Smittoidea ornatipectoralis 

 brevior, parallel to the frontal plane. But in Smittoidea evelinae the 

 avicularium is smaller and placed at a right angle to the frontal plane, 

 horizontally within the peristomial boundary, with the mandible for- 

 ward. Also, the avicularium and lyrula are about the same width. 

 Some of the inside measurements of avicularia from the Antarctic 

 sample may even be slightly narrower than the l3Tula. 



Another point of difference between S. acaroensis and S. evelinae 

 is in the nature of the distal orifice border. Levinsen pictures and 

 cites it as serrate but in S. evelinae it is smooth. 



MacGillivray (1895, p. 92, pi. 12, fig. 13) described a Tertiary fossil, 

 Porella innocua, from Victoria, Australia, which is very similar to S. 

 evelinae, differing from it only in the shape of the orifice which appears 

 longer and more square in P. innocua. His figure is too vague to 

 show the oral avicularia and he characterizes them as small. 



Lastly, Kluge (1946, pi. 2, fig. 8) pictures a Smittina glaciata 

 (Waters) 1900 that is very simdar to Smittoidea evelinae in all respects 

 except that in some zoids its avicularium may rise up on a conical peak. 



Smittoidea ornatipectoralis, new species 

 Plate 33 



Diagnosis: Zoarium encrusting. Zooecial frontal gently convex, 

 bordered by areolae and ending at edges in a thin salient rim. Sec- 

 ondary orifice a low peristome with wedge-shaped median frontal 



