NO. 2 OSBURN: eastern pacific BRYOZOA CHEILOSTOMATA 493 



tributed. The muscle attachments of the operculum are usually in the 

 form of small dots, somewhat removed from the border. Oral spines 

 present or wanting. Genotype, Cellepora coronopus S. Wood, 1850. 



The zoaria are usually encrusting and nodular, but occasionally erect 

 and branching, and without pigment. 



Schizmopora anatina (Canu and Bassler), 1930 

 Plate 62, figs. 5-6 



Osthimosia anatina Canu and Bassler, 1930 :42. 



The zoarium rises free from an encrusting base, usually on small 

 stems, to a height of 30 mm or more ; the branches more or less cylindrical, 

 the basal one as much as 6 mm in diameter, secondary ones about 3 to 

 6 mm, the lateral branches sometimes anastomosing at their tips. The 

 zooecia are moderately large, 0.60 to 0.75 mm long by 0.30 to 0.40 mm 

 wide in the procumbent marginal ones at the tips of the branches. The 

 zooecia of the secondary layers are very irregularly disposed and erect 

 or semi-erect. The frontal is considerably swollen, smooth or slightly 

 rugose and imperforate except for the usual complement of areolar 

 pores. In the marginal zooecia a tall, pointed avicularian umbo projects 

 over the aperture, its base often wider than the aperture, but in the 

 secondary layers the umbo is much reduced in size and often wanting. 

 The peristome is low, thin and without spines. The primary aperture 

 is nearly round, with a broad, shallow (sometimes slightly v-shaped) 

 sinus, length 0.14 to 0.16 mm, width 0.14 mm. The suboral avicularia 

 are small with a semicircular, bluntly triangular or slightly spatulate 

 mandible, situated a little to one side of the median line and usually 

 directed sideways ; in the marginal zooecia they are somewhat triangular 

 and mounted at one side of the high umbo, but in the secondary layers 

 they are often only slightly raised and are sometimes wanting. The 

 large interzooecial avicularia are very irregular in distribution and vary 

 much in size (0.25 to 0.50 mm long, average about 0.40) ; the mandible 

 shaped like a duck-bill, widest near the tip, with a pair of sclerites which 

 unite beyond the middle and a round lucida at a distance from the base; 

 attached by condyles or complete pivot. 



The ovicell is globular, prominent, with rather large round pores 

 arranged in quincunx over the whole frontal surface, about 0.26 mm in 

 width. 



Canu and Bassler described this species from the Galapagos Islands 

 under the genus Osthimosia Jullien, neglecting the nature of the per- 

 forated ovicell in favor of that of the frontal, but the ovicell is similar 



