634 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



In all characters, zoarial and reproductive, except the bilaminate adult 

 zoarium, this species agrees closely with P. patina and must be considered 

 congeneric with it. 



Robertson recorded it from three localities in southern California, 

 down to a depth of 32 fms. 



Type AHF no. 107. 



Type locality, Hancock Station 1662-48, off Santa Cruz Island, 

 southern California, 33°55'45''N, 119°31'05nV, at 23 fms. Also taken 

 at 1130-40, off Laguna Beach, southern California at 25 fms; at Cortez 

 Bank, 32°24'N, 119°22'30"W, at 131 fms; and at 1190, Puerto Escon- 

 dido, Gulf of California, 25°48'04''N, lll°18'53nV, in shallow water. 

 Another fine specimen from Station 275, Raza Island, Gulf of Cali- 

 fornia, 28°48'N, 113°W, at 40 fms has 4 ovicells more or less centrally 

 located and 3 others partially developed near the margins of the zoarium. 



Plagioecia grimaldii (Jullien), 1903 

 Plate 66, fig. 5 



Mesenteripora Grimaldii Jullien, 1903:118. 



Plagioecia grimaldii, Osburn, 1936:540. 



? Mesenteripora meandrina, Smitt, 1866:432. 



The zoarium consists of erect contorted folds arising from an encrust- 

 ing base to a height of 1 or 2 cm. The folds are bilamellar, the growing 

 edge showing the basal lamina with the tubules arising on both sides. 

 The colony may be stipitate, as in Jullien's figure, plate 15, fig. 4, but 

 is often broad and irregular. The embedded tubules are convex and quite 

 distinct on the surface of the zoarium, 0.25 to 0.30 mm in width, with 

 moderately deep separating grooves and perforated by numerous small 

 pores. The peristomes are usually very short, often rising scarcely above 

 the zoarial surface, but in protected areas they may rise, semierect, to 

 a length of 0.40 mm. The apertures vary considerably, from 0.14 to 

 0.18 mm and are often closed by the characteristic diaphragm with a 

 small tubule at the center. 



The ovicells, here described from Baffin Bay specimens, are variable 

 in size and form, large enough to surround 5 or 6 peristomes, prominent 

 and sharply outlined ; the ooeciostome smaller than a peristome and 

 scarcely elevated above the surface, median and terminal in position. 

 There is a tendency for the ovicells to be slightly broader than long but 

 in one case the^ length is 50% greater than the width; another much 

 smaller ovicell, which encloses only one peristome, is round. Since so 



