NO. 1 OSBURN : EASTERN PACIFIC BRYOZOA — CHEILOSTOMATA 79 



erect, one usually larger than the other. An avicularium on the proximal 

 gymnocyst, mounted on a raised projection; when an ovicell is present 

 the avicularium appears to arise from the ovicell. 



The ovicell is prominent, smooth w^ith a transverse rib and the distal 

 avicularian chamber forms a part of the rover. 



In many respects this species is so similar to T. armifera (Hincks) 

 that the latter was described as a variety. However, the distolateral 

 paired avicularia of armifera are never present in unicornis and there are 

 other slight differences. 



Hincks listed the species from Houston-Stewart Channel, British Co- 

 lumbia. A common species in the northern Atlantic ; on the North Ameri- 

 can side from Greenland south to Cape Cod, Massachusetts ; in the Arctic 

 west to the Northwest Territory, Canada. 



Hancock Stations: 1234, Santa Rosa Island, and 1245, Santa Cruz 

 Island, southern California; southern Alaska; Point Barrow, Alaska, 

 G. E. MacGinitie, collector, Arctic Research Laboratory. 



Tegella armifera (Hincks), 1880 

 Plate 9, figs. 1 and 7 



Membranipora armifera Hincks, 1880a:82. 

 Membranipora sophiae van armifera. Waters, 1889 :680. 

 Callopora unicornis var. armifera, Norman, 1903 :27. 

 Membranipora cassidata O'Donoghue, 1923 :27. 

 Tegella cassidata, O'Donoghue, 1926 :36. 

 Tegella unicornis var. armifera, Osburn, 1933 :24. 



This species is very similar to unicornis Johnston, except for the pres- 

 ence of the lateral avicularia. This difference is so constant that I believe 

 armifera should be given specific standing. There is one other character 

 that may be of some importance and that is the occasional presence of a 

 curved, pointed spine which bends somewhat over the opesia and which 

 I have never observed in unicorfiis; also armifera is considerably larger. 



The zoarium encrusts shells, stones, algae and occasionally even small 

 stems. The zooecia are rather large and have a wide range in measure- 

 ment, length 0.60 to 0.80 mm, width 0.35 to 0.50 mm, and occasionally 

 transcending these measurements in either direction ; shorter zooecia are 

 usually correspondingly wider, the ovate opesia varying with the form of 

 the zooecium. The basal gymnocyst is well developed and bears an avicu- 

 larium; the descending cryptocyst is somewhat thick and granulated. The 

 spines are as follows: a small erect spine at or near each distal corner, 

 frequently wanting; a tall stout spine on either side near the attachment 



