82 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



cyst granulated, without horizontal lamina; walls high, the rim thin 

 when young. Opesia elliptical or oval. There is an erect hollow spine on 

 one side at the base of the operculum and frequently a smaller one on 

 the opposite side; proximal to these on the sides are frequently 1 to 3 

 smaller curved spines bending somewhat over the opesia. An avicularium 

 is usually present on every zooecium, large, about half the zooecial length, 

 the mandible elongate triangular, its tip slightly rounded and strongly 

 decurved, pointing forward and to one side of the opesia. 



The primary ovicell is small ; the ectooecium forms a complete cover 

 separated from the endooecium. The wall of the distal avicularium usu- 

 ally fuses completely with the ectooecium. 



Miss Robertson first listed the species from Alaska and Queen Char- 

 lotte Islands as M. unicornis and later described it as M. occultata, over- 

 looking the fact that Waters had previously applied that name to another 

 species. O'Donoghue listed it for a number of British Columbia locali- 

 ties, and Sakakura ( 1935 :8) recorded it from Japan. 



Hancock Station 1662-48, Santa Barbara Island, California. Also 

 from Monterey Bay, (Robertson), Dillon Beach, (Menzies), California, 

 and Clayoquot Sound, British Columbia (E. F. Ricketts). The known 

 range is from southern Alaska to southern California. 



Tegella arctica (d'Orbigny), 1851 

 -'"^ Plate 9, fig. 6 



Membranipora conferta Hincks, 1882:249. 

 Membranipora sophiae form matura, Hincks, 1884:9. 

 Callopora arctica, Osburn, 1919 :608. 



Zoarium encrusting on rocks and shells. Zooecia of moderate size, 

 about 0.60 mm long ; the opesia elliptical or ovate, averaging about 0.40 

 mm long; gymnocyst well developed; descending cryptocyst narrow and 

 granulated; the mural rim bears on each side 2 to 4 stout flattened 

 spines which bend down closely over the opesia, the pointed tips some- 

 times overlapping; the absence of erect hollow spines distinguishes this 

 species readily from others of the genus in this region, though a minute 

 vestigial spine may occur at the base of the lateral avicularium. The 

 mural rim also bears on each side a small elevated avicularium with a 

 triangular mandible which is directed distally and somewhat toward the 

 midline. A larger avicularium may be present in the usual position on the 

 gymnocyst, but is never so much enlarged as in the other species, nor does 

 the chamber cover the ovicell to such an extent ; often they are wanting 

 over most of the zoarium. 



