NO. 3 OSBURN: EASTERN PACIFIC BRYOZOA CYCLOSTOMATA 633 



size in sarniensis, and in patina there is much variation in width. 



P. sarniensis has now been found in so many parts of the world that 

 its distribution must be considered cosmopolitan. Hincks first listed it 

 for Pacific waters at Cumshewa, British Columbia, and O'Donoghue 

 recorded it from Banks Island and Lowe Inlet, British Columbia, and 

 the San Juan Islands, Puget Sound. 



Hancock Stations: 484, Barrington Island, Galapagos, 0°49'S, 90° 

 06'40nV, 52 fms; 423-35, oflF Port Utria, Colombia, 5°59'2(y'N, 77° 

 2r50''W, at 20 fms; 276, San Esteban Island, Gulf of California, 

 28°38'50"N, 112°36'W, at 32 fms; 72, Guadalupe Island, off Lower 

 California, 29°N, at 17 fms; Santa Barbara, Anacapa and San Clemente 

 Islands, off southern California; and San Juan Islands, Puget Sound, 

 Washington. 



PlagioecJa tortuosa new species 

 Plate 67, figs. 8 and 9 



Mesenteripora meandrina, Robertson, 1910:251 (not Wood, 1844:14). 



Dr. Alice Robertson has given an excellent description of the zoarium : 

 "Zoarium bilaminate, forming a contorted, convoluted mass . . . begin- 

 ning as a simple, primitive disk from which there grow tubular zooecia 

 curving in opposite directions, and forming a fan-shaped expansion 

 similar to any young tubuliporidian colony. The two layered condition 

 results from the ridges which occur at irregular intervals over the 

 unilaminar sheet, . . . and which growing upward form the erect, 

 bilaminar layers, the laminae becoming highly convoluted." The en- 

 crusting base sometimes covers a considerable area before the bilaminate 

 folds are formed. 



The zooecia are alternate, in quincunx, embedded but with the frontal 

 surface convex, with numerous pores and sometimes transversely ribbed. 

 The erect tubules or "peristomes" are usually short but may be as much 

 as 0.50 mm in length, narrowing only slightly, perforated only near the 

 base, about 0.13 mm in outside diameter; the aperture short oval or 

 round and about 0.10 mm in diameter. 



The ovicell, partially described by Robertson, is a distinct inflation 

 which is usually considerably broader than long, surrounding 6 to 12 

 peristomes. The ooeciostome, which Robertson was unable to find, is 

 sub-terminal, median, somewhat removed from the distal border, short, 

 erect and slightly expanded at the tip, the pore round, 0.08 mm in 

 diameter and the tip expanded to 0.13 mm. 



