FOSSIL BRYOZOA FROM THE WEST INDIES. 89 



Occurrence. Lower Miocene (Bowden horizon), Cercado de Mao 

 and Rio Cana, Santo Domingo, and Bowden, Jamaica. 



Family STEGANOPORELLID^ Levinsen, 1909. 

 Genus STEGANOPORELLA Smitt, 1873. 

 Steganoporella parvicella, new species. 

 (Plate 6, Figures 6 to 9.) 



The following is a description of this species : 



The zoarium is unilamellar, incrusting algae or bryozoa. The zooecia are 

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

 salient, finely granular. The cryptocyst is finely porous; the opesium is 

 irregular or semilunar, a little elongate; the polypidian tube forms a rect- 

 angular surface, salient and excentric between the two dissimilar opesiular 

 indentations. The large zooecia (B) are provided with a large distal floor, and 

 the polypidian tube is almost median. 



Measurements. Opesium of small zooecia: ho = 0.34 to 36 mm., to = 0.16 

 to 0.30 mm.; small zooecia (a): Lz = 0.50 to 0.76 mm., Zz = 0.50 mm.; opesium 

 of large zocecia (b): ho = 0.24 to 0.30 mm., Zo = 0.36 to 0.40 mm.; large zooecia 

 (B): Lz = 1.00 to 1.10 mm., te = 0.44 to 0.56 mm. 



Affinities. The dimensions are quite variable, but they are always 

 smaller than those of Steganoporella magnilabris Busk, which this 

 species resembles in all its other characters. 



Occurrence. Lower Miocene (Bowden horizon), Cercado de Mao 

 (Bluff 3), Santo Domingo, and Bowden, Jamaica. 



Family ASPIDOSTOMDXaS Canu, 1908. 

 Genus LABIOPORA Levinsen, 1909. 



No ovicell; distinct, raised margins; frontal wall of polypidian tube not 

 quadrangular and not surrounded by projecting flanges. Polypide tube bila- 

 biate, on either side connected with the lateral wall by a vertical calcareous 

 lamina; multiporous septulse. 



Genotype. Labiopora crenulata Levinsen, 1909, Recent. 



Labiopora miocenica, new species. 

 (Plate 6, Figure 1.) 



The following is a description of this species : 



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

 the mural rim is quite thin, round. The cryptocyst is little deep, flat, and 

 formed of a tremocyst superposed on an olocyst perforated with corresponding 

 pores. The opesium is transverse, terminal, or placed at the base of a funnel, 

 formed by the much-developed vestibular arch. The polypidian tube is 

 visible, wide, median. 



Measurements. Opesium: ho = Q.W mm., Zo = 0.24 to 0.28 mm.; zocecium: 

 Lz = 0.50 to 0.64 mm., /z = 0.32 to 0.34 mm. 



Affinities. This new species differs from Labiopora crenulata Levin- 

 sen, 1909, in the wide form of the zooecia and in its transverse opesium. 

 The only fragment found has been figured. 



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

 Domingo. 



