GEOLOGY AND PALEONTOLOGY OF THE WEST INDIES. 



Family THALAMOPORELLIDjE. 



Genus THALAMOPORELLA Hincks, 1887. 



Thalamoporella granulata Levinsen, 1909. 



(Plate 2, Figure 14.) 



Thalamoporella granulata Levinsen, Morphological and Systematic Studies on the Cheilos- 

 tomatous Bryozoa, p. 188, plate vi a, fig. 1, 2, plate vi, fig. 5, 1909. 



Thalamoporella granulata Osburn, The Bryozoa of the Tortugas Islands, Florida, Carnegie 

 Inst. Wash. Pub. No. 182, p. 197, fig. 8, 1914. 



Measurements. Opesium: ho = 0.16 to 0.18 mm., Zo = 0.16 to 0.18 mm.; 

 zooecium: Lz = 0.80 mm., te = 0.50 mm. 



Affinities. We possess only a small fragment consisting of two 

 zooecia; we are not certain, therefore, of our determination, as this has 

 been made almost entirely on the micrometric measurements. 



The opesium is oval, the point above; the cryptocyst is granulated; 

 the mural rim has a width of 0.08 mm. and is granulated transversely. 



Occurrence. Lower Miocene (Bowden horizon), Rio Cana, Santo 

 Domingo. 



Habitat. Andaman or Nicobar Islands? (Levinsen); Tortugas 

 Islands, Florida (Osburn). 



Thalamoporella biperforata, new species. 

 (Plate 6, Figures 10 to 15.) 



The following is a description of this species: 



The zoarium is bilamellar. The zooecia are elongate, distinct, rectangular; 

 the mural rim is thin, salient, beveled, and bears two hollow tubercles on each 

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

 widely spaced pores and with numerous small pores closely placed together; 

 the opesiules are very large, far distant from the aperture, placed symmetri- 

 cally, 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 cryp- 

 tocyst is perforated by two opesiules; the opesium bears two lateral denticles 

 serving as pivot to the corneous onychocellarium. 



Measurements. Opesium of zocecium: ho = Q.W to 0.12 mm., Zo = 0.14 mm.; 

 zooBcium: La; = 0.54 to 0.60 mm., te = 0.34 to 0.40 mm.; opesium of onycho- 

 cellarium: ho 0.24 mm., Zo = 0.12 mm.; onychocellarium: Lo = 0.90 mm., 

 Zo = 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 aper- 

 ture 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 provided with two opesiules, which are not figured by 

 Levinsen in the numerous drawings which he has given. 



