318 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



rather large pores; an umbo often present behind the aperture but fre- 

 quently wanting. Aperture rounded distally, a rounded sinus on the 

 proximal border ; the thickening of the frontal does not encroach on the 

 peristome which is low and smooth. Pointed avicularia are present, usually 

 one at the side of the aperture with the triangular mandible directed 

 more or less forward, but they may be turned in any direction and often 

 they are wanting over large areas of a colony ; they vary greatly in size 

 and height of the avicularian chamber. Zooecial length, 0.50 to 0.60 mm, 

 width 0.30 to 0.45 mm; aperture 0.13 to 0.15 mm long by 0.12 to 0.14 

 mm wide. 



Ovicell salient, porous, often decorated with marginal costae and 

 with an umbonate process on the top in higher calcification. 



Widely distributed in the North Atlantic, Indian and western Pacific 

 Oceans, on the eastern American coast abundant as far south as Brazil. 

 It has not been recorded from the Pacific coast of the Americas by any 

 of the earlier students of the Bryozoa, but is a rather common species in 

 the bays where oysters from the Atlantic coast have been planted, and 

 it seems probable that it may have been introduced in recent years. 



Hancock Stations: 1130-40 off Laguna Beach, 29 fms; 1222-41 and 

 1449-42, Newport Harbor on piles; Corona del Mar on piles; Elkhorn 

 Slough, Monterey Bay, shallow water; Dillon Beach on piles (R. J. 

 Menzies), all on the coast of California in shallow water. Also one 

 small colony from James Island, Galapagos, 22 fms. 



Schizoporella trichotoma (Waters), 1918 

 Plate 37, fig. 3 



Schizoporella trichotoma'W aters, 1918:19. 

 Schizopodrella trichotoma, Hastings, 1930:720. 



Zoarium encrusting, usually in a single layer. The zooecia are of 

 moderate size, exceedingly variable in their dimensions, usually ranging 

 between 0.40 and 0.65 mm long by 0.25 to 0.40 mm wide, occasionally 

 broader than long; distinct, considerably inflated; the front a smooth 

 tremocyst with numerous pores which have a stellate appearance. The 

 primary aperture is rounded distally, nearly straight on the sides to the 

 large cardelles and with a u-shaped or somewhat v-shaped proximal 

 sinus. A thin, slightly raised peristome surrounds the aperture distal to 

 the cardelles and bears about 4 minute and evanescent spines. The oper- 

 culum is well chitinized, with a pair of sclerites which are diagonal in 

 position and nearly meet at some distance from the distal border. Avicu- 

 laria have not been found. 



