NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA CYCLOSTOMATA 631 



7. Zoarium Irregularly rounded, peristomes thin, 0.09 mm at 



their tips; ovicell only moderately broad sarniensis 



Zoarium lobate, peristomes 0.13 mm at their tips; in the one 

 specimen there are two simple, narrow ovicells and one ex- 

 panded one, the ooeciostome slightly subterminal . . ambigua 



Plagioecia patina (Lamarck), 1816 

 Plate 73, fig. 4 



Tubulipora patina Lamarck, 1816:163. 

 Diastopora patina, Hincks, 1880:458; 1884:206. 

 Diastopora patina, O'Donoghue, 1923:14. 

 Plagioecia patina, O'Donoghue, 1926:21. 



Zoarium variable in form, rounded or lobate; entirely encrusting, or 

 partially free. The zoids are embedded for most of their length, the 

 free part of the tubules, "peristomes," being semierect and usually short. 

 The apertures are somewhat elliptical or nearly round, measuring about 

 0.10 by 0.12 mm. The embedded portions of the zoids are slightly convex 

 and are perforated by minute pores. The peristomes show no tendency 

 to be arranged in series, and are not connate even at the base. In older 

 parts of the colony, especially, the apertures become closed by a peculiar 

 calcified membrane which is perforated either by a number of pores or 

 by a single larger tubular pore. The basal lamina often forms a distinct 

 border beyond the functional zoids. 



The ovicell is a prominent swelling, moderately large and distinct, the 

 edges usually sharply outlined. Normally it is transversely very elongate, 

 several times as wide as long, but varying considerably in size and form. 

 Usually a number of peristomes are surrounded, to 7 in my specimens. 

 The ooeciostome is terminal and free between the zooecial series, ordi- 

 narily occupying a small notch in the middle of the distal side; it is 

 rather short and either erect or flexed slightly toward the proximal part 

 of the zoarium, the aperture rounded and 0.06 to 0.08 mm in diameter. 



This well-known Atlantic species resembles P. sarniensis in its general 

 appearance, but the zooecia are distinctly larger with shorter peristomes, 

 and the ovicell is much wider transversely. On the Pacific coast it was 

 first noted by Hincks at Cumshewa, and later by O'Donoghue at Bull 

 Passage, British Columbia. 



Hancock Stations: 143-34, Wenman Island, 100 fms, 147-34, Albe- 

 marle Island, 30 fms, and 352-35, Chatham Island, 35 fms, Galapagos; 

 299, San Jose del Cabo at the southern tip of Lower California, 82 

 fms; 72, Guadalupe Island off Lower California, 17 fms; Santa Barbara 



