84 BULLETIN 125, LTj^ITED STATES NATIONAL, MUSEUM. 



Each distal wall and the distal half of each lateral wall with a row (6-8) of one or 

 two pored rosette plates [septulae]. A longitudinal series of parietal muscles is 

 placed on each side between the cryptocyst and the covering membrane. 



Genotype. — Microporina {Cellaria) boreal is Busk and Microporina {Micropora) 

 eZon(/ata Hincks, 1880. Range: Campanian, Recent. 



Homalostega amphora Marsson, 1887, from the Campanian of Riigen, also 

 belongs to this genus. 



Genus CORYNOSTYLUS Canu and Bassler, 1919. 



1919. Corynostylus Canu and Bassler, Geology and Paleontology of the West Indies, Bryozoa, 

 Publication of the Carnegie Institution of Washington, No. 291, p. 86. 



No ovicell. The opercular valve articulates on two condyles. The zooecia are 

 club shaped and provided with a gymnocyst. The zoarium is articulated. 



Genotype. — Corynostylus lahiatus Canu and Bassler, 1919. Miocene. 



This genus has no recent equivalent but its structure is easy to interpret. 

 The two condyles serve as a hinge for the strongly cliitinized opercular valve. The 

 lower part of the opesium placed below served evidently as passage for the opesiular 

 fibers attached to the ectocyst. The deep cavity of the cryptocyst served as a 

 hydrostatic apparatus for the entrance and exit of the polypide. Like most of 

 the articulated genera, the zoarium in this one probably was fastened on large 

 mobile algae. 



CORYNOSTYLUS LABIATUS Canu and Bassler. 1919. 



Plate 2, figa. 11-13. 



1919. Corynostylus lahiatus Canu and Bassler, Geology and Paleontology of the West Indies. 

 Bryozoa, Publications Carnegie Institution of Washington, No. 291, p. 87, pi. 2, figs. 11-13. 



Description. — The zoarium is articulated and formed of long regular segments. 

 The segments are compressed, bilamellar, formed of three longitudinal rows of 

 zooecia on each side. The zooecia are elongate, oval, distinct, rounded in front, 

 narrowed behind and are provided with a convex gynmocyst with large pores; 

 the mural rim is thick, regular, granular. The opesium is elongate, oval, pro- 

 vided with a proximal, salient lip placed between two rounded opesiular indenta- 

 tions. The two condyles are quite salient. The cryptocyst is deep and smooth. 



ir 4 m ■ f^o = 0.12mm. „ . (Z2; = 0.50mm. 



Measurements. — Opesia , „ , „ Zooecia , 



^ Uo = 0.10mm. 1 /2 = 0.26 -0.28 mm. 



Affinities. — The first zooecium of each segment is radicular; it gives rise to 

 three polypidian zooecia. 



Occurrence. — Lower Miocene (Bowden hori»on) : Cercado de Mao, Santo Do- 

 mingo (common). 



Holotype.— Cat. No. 68514, U.S.N.M. 



CORYNOSTYLUS ELLIPTICUS Canu and Bassler, 1919. 



Plate 2, figs. 8-10. 



1919. Corynostylus ellipticus Canu and Bassler, Geology and Paleontology of the West Indies, 

 Bryozoa, Publications of the Carnegie Institution of Washington, No. 291, p 87 pi 2 

 figs. 8-10. 



Description.— The zoarium is articulated. The segments are formed of two 

 longitudinal rows of zooecia placed only on one side of the zoarium. The zooecia 



