62 BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 



THALAMOPORELLA BIPERFORATA Canu and Sassier, 1919. 



Plate 6, figs. 10-15. 



1919. Thalamoporella biperforata Canu and Bassler, Geology and Paleontology of the West Indies, 

 Bryozoa, Publication Carnegie Institution of Washington, No. 291, p. 88, pi. 6, figs. 10-15, 



Description. — Tlie zoarium is bilamellar. The zooecia are elongate, distinct 

 rectangular; the mural rim is thin, salient,__bevelled, and bears two hollow tubercles 

 on each side of the aperture. The cryptocyst is deep, flat, ornamented with large 

 \vndely spaced pores and with numerous small pores closely placed together; the 

 opesiules are very large, far distant from the apertura, placed symmetrically, but 

 very unequal in size. The apertura is transverse, oval; the proximal border is 

 always concave and the polypidian tube is limited by two small lateral indentations. 

 The reticulocellarium is large, quite elongate; its cryptocyst is perforated by two 

 opesiules; the opesium bears two lateral denticles serving as pivot to the corneous 

 mandible. 



Measurements. — Opesium of zooeciima , „'. . 



I 40 = 0.14 mm. 



„ . ( Zz = 0.54-0.60 mm. 



Zooecium noin^n 



I Z0 = 0.34-0.40 mm. 



^ . J. 1 11 • (A.on = 0.24 mm. 

 Upesium 01 onvcnocellarium- , „ ,„ 

 ^ ~ I ton = 0.12 mm. 



^ 1 „ . (Zoji = 0.90 mm. 



Unvchocellanum , „„„ 



Uon = 0.30 mm. 



Affinities. — The oral tuberosities are quite variable in size; they are often 

 replaced by two fossettes. 



This species is characterized by its onychocellarium, which resembles that of 

 Thalamoporella granulata Levinsen, 1909, figured by Osburn, 1914. It differs, 

 however, in the very different oval form of its apertura and in the presence of oral 

 tuberosities. In its tuberosities this species is quite close to Thalamoporella rozieri 

 Savigny-Audouin, 1826. It differs from it in the form of its onychocellarium pro- 

 vided with two opesiules, which are not figm-ed by Levinsen in the numerous draw- 

 ings which he has given. 



Occurrence.— Lov^ev Miocene (Bowden horizon) : Cercado de Mao, Rio Cana and 

 Rio Gurabo, Santo Domingo; and Bowden, Jamaica (common). 



Cotypes.~G&i. No. 68483, 68484, U.S.N.M. 



Family STEGANOPORELLIDAE Levinsen, 1909. 



Genus STEGANOPORELLA Smitt, 1873. 



(For description see Bulletin 106, U. S. National Museum, p. 259.) 



STEGANOPORELLA PARVICELLA Canu and Bassler, 1919. 



Plate 6, figs. 6-9. 



1919, Sleganoporella parvicella Canu and Bassler, Geology and Paleontology of the West Indies, 

 Bryozoa, Publication of the Carnegie Institution No. 291, p. 89, pi. 6, figs. 6-9. 



Description.— The zoarium is unilamellar incrusting algae or bryozoa. The 

 zooecia are distinct, elongate, separated by a shallow furrow; the mural rim is thin, 



