50 PKOCEEDIXCS OF THE Is'ATiONAL MUSEUM. vol.61. 



raised almost vertically. The ovicell is suborbicular, convex, sub- 

 symmetrical; the oeciostome is elliptical, transverse, siibcentral. 

 orthogonal, 



[ Diameter of tubes and of 



Measurements. — | peristomes 0.26 mm 



I Dimensions of oeciostome .'^3 by 0.10 nini 



The general aspect is quite irregular and does not permit of con- 

 staTit n^.icrometric measurements; it appears like a club bristling witli 

 spines. 



Occun'ence. — Sirun (Sulu Archipelago, Tawi Tawi group) ; Philip- 

 pine Islands {Alhatross station D. 5151). 



Holotype.—Q2it. No. 7376, U.S.N.M. 



Genus IDMONEA Lamouroux, 1821. 



IDMONEA MAGNA Canu and Bassler, 1920. 



Plate 8, fij,'. 11. 



1920. Idmonea magna Canu and Basslek, North American Early Terti:iry 

 Bryozoa, Bull. 106, U. S. National Museum, p. 772, pi. 137, figs. 1-18. 

 This very abundant Early Tertiary bryozoan is an excellent exam- 

 ple of the number of specimens which must be examined before an 

 ovicell is discovered. In this case literally thousands of specimens 

 were glanced over before the ovicelled one here figured was found. 

 Fortunately the ovicell is not necessary in the identification of tlie 

 species. 



Occvrr^ence. — Eocene (Jacksonian) : Atlantic and Gulf States. 



Genus PLEURONEA Canu and Bassler, 1920. 



PLEURONEA FENESTRATA Busk, 1859. 



Plato 10, figs. 1-5. 



1920. Plcuroncu fcnestraia Canu and Basslkr. North American Early 

 Tertiary Bryozoa, Bull. 106, U. S. National Museum, p. 766, pi. 114, 

 figs. 1-18 (bibliography and distribution). 



We have had the good fortune to discover many ovicelled speci 

 mens of this species, whereby we were able to study its variations. 

 They are iis numerous as in the genus TuhuJipora. The ovicell ap- 

 pears symmetrical and median (fig. 3) on certain specimens; in 

 others, it is sometimes a little developed on one side (fig. 1) ; finally 

 it may surround a part of the zoarium and be developed on the 

 frontal (fig. 2). 



The dorsal of this species presents the most varied aspects. We 

 have discovered some specimens on which the tergopores open at 

 the bottom of pseudosulci (fig. 5). These latter are branched, 

 irregular, and undulate, in Avhich they differ from true longitudinal 

 .«ulci. 



