108 PROCEEDINGS OF THE NATIONAL, MUSEUM. vol.61. 



Family TRETOCYCLOECIIDAE Canu, 1919. 

 Rectangulata in which the ovicell is orbicular, flat, smooth, regu- 

 lar and limited, traversed by the tubes and sometimes by adjacent 

 mesopores. 



This family corresponds to the Diaperoeciidae in the Parallelata, 

 but differs from it in addition to its axis arranged perpendicularly 

 to the zooecial axis instead of parallel, in the flat orbicular and not 

 globular form of the ovicell, and in the presence of mesopores. 

 The genera referred to this family at present are as follows: 

 Tretocycloecia Canu, 1919. Cretaceous-Recent. 

 Partretocycloecia Canu and Bassler, 1920. Eocene. 

 Telopora Canu and Bassler, 1920. Recent 

 Alveolaria Busk, 1859. Pliocene. 

 Psilosoleri, new genus. Pleistocene, Recent. 

 The simplest genera are the most recent, and the decadence of 

 the Cyclostomata is well shown by the family. 



Genus TRETOCYCLOECIA Canu, 1919. 



1919. Tetrocycloecia (in error for Tretocyvloecia) Canu, Etudes sur les 

 Ovicelles des Bryozoaires Cyclostonies (2), Bulletin Socigte Geologique 

 de France, ser. 4, vol. 17, p. 346. 



The tubes are cylindrical. The mesopores are irregularly directed ; 

 their walls are vesicular. The tubes which perforate the ovicell 

 are accompanied by the adjacent mesopores. 



Genotype. — Tretocycloecia {Heteropord) dichotovm Reuss, 1847 

 (not Hagenow, 1851). 



Range. — Midway an-Recent. 



TRETOCYCLOECIA DICHOTOMA Reuss, 1847. 



1847. Hetcropora dichotoma Reuss, Die fossilen Polyparien des Wiener 



Tertiarbeckens, p. 35, pi. 5, fig. 20. 

 1877. Eeteropora dichotoma Manzom, I Briozoi fossili del Miocene d'Aus- 



tria ed Ungheria, p. 35, pi. 12, fig. 46. 

 1859. Heteropora pustulosa Busk, A Monograph on the Fossil Polyzoa of 



the Crag, p. 122, pi. 19, fig. 6 ; pi. 20, fig. 1. 



1920. Tretocijcloecia dichotoma Canu and Bassler, North American Early 

 Tertiary Bryozoa, Bull. 106, U. S. National Museum, p. 828, fig. 275. 



The studies relative to this species have been made from the speci- 

 mens collected in France. We are not entirely certain of our de- 

 termination, for we have never been able to procure Austrian speci- 

 mens for comparison. 



The zoarium is quite variable ; massive, reticulate, but more often 

 arborescent and cylindrical. 



The tubes are cylindrical, quite long, bifurcating chiefly in the 

 median region at all heights. They are curved at right angles at 



