NO. 1 OSBURN: EASTERN PACIFIC BRYOZOA CHEILOSTOMATA 87 



a blunt tubercle. The opesia is oval, large, about 0.65 mm long by 0.35 

 mm wide, the mural rim thin and the descending cryptocyst narrow and 

 granulated. There are usually six spines on each side. Avicularia are few 

 and widely scattered, vicarious on zooeciules, the chamber rather large 

 (about 0.40 by 0.50 mm) ; the avicularium small, short oval, wnth an 

 elevated rounded rostrum which is crenated on the distal edge ; the mandi- 

 ble semicircular, with strong hinge denticles. 



The ooecium has a large circular membranous area on its distal end. 

 This is not due to incomplete growth as the border of the fenestra is 

 thickened and finely beaded and the same characters appear on all of 

 the ooecia. The ooecium is very prominent, hjperstomial, broader than 

 long, averaging 0.30 mm wide by 0.26 mm long, the surface smooth and 

 shining, the proximal edge slightly elevated to form a lip, the aperture 

 not closed by the operculum. 



Type, AHFno. 21. 



Type locality, Hancock Station 446, James Bay, James Island, Ga- 

 lapagos Island, 54 fms. Also at Sulivan Bay, James Island, and at 

 450, 0°55'S, 90°30'W, Galapagos, 14 to 60 fms. 



Retevirgula areolata (Canu and Bassler), 1923 

 Plate 7, fig. 6 

 Mystriopora ? areolata Canu and Bassler, 1923:19. 



Zoarium thin, unilaminar, encrusting but loosely attached by the short 

 dorsal tubercular processes of the zooecia ; zooeciules of various sizes are 

 of frequent occurrence. The zooecia, while often in contact on the sides, 

 are in general more loosely attached to each other than in R. lata; the 

 fenestrae are larger and the connecting tubes longer. Zooecium moder- 

 ately large, 0,65 mm long by 0.40 mm wide, the gymnocyst is usually 

 well developed, narrowed proximally to the tubular process which con- 

 nects it with the preceding zooecium. The opesia is distinctly narrower 

 in proportion than in lata, elliptical, averaging about 0.55 mm long by 

 0.26 mm wide. The mural rim is elevated, moderately thin and the 

 cryptocyst narrow and granulated. There are 6 or 7 tall strong spines 

 on each side, the two distal pairs erect and the others leaning somewhat 

 over the opesia. There are also small spines on the avicularian rims. The 

 avicularia are small, rounded, elevated, the mandible semicular and 

 attached by strong hinge denticles. 



The ooecia are prominent, but difficult to see among the tall spines, 

 globular and smooth, with a rounded or elliptical fenestra near the mid- 

 dle of the front, width and length about 0.26 mm. 



