AKT. 13 BRYOZOAN FAUNA CANU AND BASSLER 43 



The genus Schismopora and Osthiviosa are poorly defined by 

 the perforation of the ovicells; the frontal calcification appears to 

 furnish the better distinctive character. 



Biology. — ^We have observed specimens living and ovicelled in 

 April, 1888. 



Occurrence. — Galapagos Islands, D. 2813 and D. 2815. 



C otijpes. —C2ii. Nos. 8516, 8517, U.S.N.M. 



Genus HIPPOPORIDRA Canu and Bassler, 1927 



HIPPOPORIDRA GRANULOSA, new species 



Plate 8, Fi^iures 1, 2 



Description. — The zoarium incrusts shells. The zooecia ar« 

 oriented or cumulate. The oriented zooecia are distinct, separated by 

 a furrow, ovoid, a little elongated; the frontal is quite granular, 

 convex, surrounded by scattered areolar pores. The aperture is small, 

 elongated, and formed of a large circular anter and of a very small 

 rounded poster, surmounted by six distal spines. In the vicinity of 

 the aperture there is sometimes a small avicularium of inconstant 

 form and position. The cumulate zooecia are erect and form very 

 salient verrucosities. The operculum bears two sinuous bands. 



Measurements. — 



\ha=0.V2 mm. fZs = 0.40-0.50 mm. 



Aperturaj ^^^ 0.07-0.09 mm. Zooecia | /^ = 0,30^0.35 mm. 



Variations. — The width of the aperture is rather variable; it has 

 in consequence a great variability in the operculum. On a dozen of 

 opercula visible in our preparation not one is exactly similar to the 

 other, but all, however, have their two characteristic sinuous bands. 

 There are no dietellae. 



Afflmties. — This species is very well characterized by its frontal 

 granules and the large number of oriented zooecia. We have not 

 observed the large interzooecial avicularia as in Hippoporidra hran- 

 coensis Calvet, 1907, and Hippopondra edax Smitt, 1873. 



Our specimen was living but very incomplete, since it did not show 

 an ovicell. It incrusts the two sides of a shell ; the cumulate cells are 

 arranged only on the edge of the shell. The latter then must have 

 been attached to some more or less floating tuft and did not live on 

 the bottom when dredged. 



Occurren.ce. — Galapagos Islands, D. 2813. 



HoJotype.—C^t. No. 8518, U.S.N.M. 



Genus HIPPOTREMA Canu and Bassler, 1927 



HIPPOTREMA(?) SPICULIFERA, new species 



Plate 8, Figures 3-5 



Description. — The zoarium is free, cylindrical, branching or in 

 thick fronds. The zooecia are cumulate, small, oblique; the frontal 



