636 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Canu and Bassler placed the species in their genus Diaperoecia be- 

 cause of the peristomes surrounded by the ovicell, but indicated that 

 "It is not yet a true Diaperoecia." As a matter of fact, the ovicell is 

 almost exactly like that of Plagioecia patina in form and location as well 

 as the nature of the ooeciostome. The perforation of the ovicell by the 

 peristomes sometimes occurs in its relatives, patina and sarniensis, and 

 in a specimen of P. (Alicroecia) tubiabortiva (Canu and Bassler, 1930) 

 I have observed as many as 8 such enclosed peristomes. The closure of 

 the peristomial apertures also is exactly like that in patina, a porous 

 calcified membrane with a minute short tubule at the middle. 



Our best developed specimen measures about 35 mm across the en- 

 crusting base and the fenestrate erect portion is about 60 mm high and 

 wide, with 7 complete fenestrae. In most cases the growing edges of 

 the branches are oriented in the same direction. 



Described from the Galapagos Islands, Albatross Station D. 2815. 



Hancock Stations: 143-34 Wenman Island; 170-34, Chatham Island; 

 201-34, Hood Island; 450, Albemarle Island; 452, Charles Island, and 

 453, Gardner Island, all from the Galapagos. Also at 1662-48, Santa 

 Cruz Island, southern California; and collected by Dr. Carl L. Hubbs 

 at Guadalupe Island, off Lower California. The geographic range is 

 wide, from Santa Cruz Island, southern California (33°35'45''N) to 

 Hood Island, (1°21'55"S), and the bathymetric range from 23 to more 

 than 100 fms. 



Plagioecia tubiabortiva (Canu and Bassler), 1930 



Plate 73, fig. 2 



Microecia tubiabortiva Canu and Bassler, 1930:48. 



The zoarium is broad and flat, with a very irregular outline; the 

 surface even, with smooth areas free from apertures and consisting of 

 aborted tubules. The zooecial tubes are completely immersed, except for 

 the very short, semierect peristomes which usually project only slightly 

 above the crust. The diameter of the peristomes is 0.12 or 0.13 mm, that 

 of the apertures 0.10 or 0.11 mm. The aperture is rounded to slightly 

 elliptical. The peristomes are irregularly spaced, never connate and not 

 in series. The basal lamina usually forms a distinct border. 



The ovicell is a low inflation, rounded, expanded laterally or irregular 

 in outline, usually surrounding a few peristomes (8 in one case). The 

 ooeciostome rises barely above the surface, median and terminal in posi- 

 tion, its aperture measuring about 0.06 mm. 



