FOSSIL BRYOZOA FROM THE WEST INDIES. 91 



This species may easily be confused with Stylopoma spongites Pallas, 

 1766; it is distinguished from it by the wide, proximal sinus of its 

 aperture and by the quite different form of its ovicell. 



At Bowden we have found only a single specimen, but we are quite 

 certain of its determination. 



This recent species, which is abundant throughout the European 

 Tertiary, is on the contrary very rare in America; but its geologic 

 distribution there appears to be almost identical. 



Occurrence. Lower Miocene (Bowden marl), Bowden, Jamaica. 



Geologic distribution. In Europe since the Stampian; in America, 

 Miocene of Maryland (Ulrich). We have also discovered it in the 

 Miocene at Wilmington, North Carolina, and Muldrow's Mills, South 

 Carolina. 



Habitat. Atlantic, Mediterranean. 



Genus STYLOPOMA Levinsen, 1909. 



Stylopoma spongites Pallas, 1766. 



(Plate 1, Figure 13.) 



Cellepora informata Lonsdale, Report on the Corals from the Tertiary Formations of North 

 America, Quart. Journ. Geol. Soc. London, I, p. 505, fig. 0, 1845. 



Hippothoa spongites Smitt, Floridan Bryozoa, part I, Kongl. Svenska, Ventenskaps-Akade- 

 miens Handlingar, X, No. 11, p. 42, plate vm, fig. 161, 162, 163, 1872. 



Schizoporella informata Ulrich and Bassler, Maryland Geological Survey, Miocene, p. 419, 

 plate 114, figs. 6-10, 1904. 



Affinities and variations. The specimen from the Anguilla forma- 

 tion certainly represents the narrow variation of this species. It is 

 incrusting a sponge. At Bowden we have found only a single specimen. 



The apertura is quite characteristic ; the sinus is rectilinear and quite 

 narrow; the tongue of the operculum which covers it is rigid. 



This species is one of the more common of the American species of 

 the Miocene and Pliocene. Its geographic distribution was limited by 

 the equator and 40 parallel. Like Callopora tenella, it is now living 

 in the waters off Florida. 



Occurrence. Lower Miocene (Bowden marl), Bowden, Jamaica 

 (very rare); Oligocene (Anguilla formation), southwest side of Crocus 

 Bay, Anguilla, Leeward Islands, T. W. Vaughan, collector, 1914, loc. 

 No. 6894. 



Habitat. Florida (Smitt, Osburn). 



Genus STEPHANOSELLA Canu and Bassler, 1917. 



Stephanosella biaperta Michelin, 1842. 

 (Plate 1, Figures 16 to 18.) 



Eschara biaperta Michelin, Iconographie zoophytologie, p. 330, 1842. 



Hippothoa biaperta Smitt, Floridan Bryozoa, pt. II, Kongl. Svenska, Vetenskaps-Akad. 



Handlingar, X, p. 46, plate vra, figs. 173-176, 1873. 

 Schizoporella biaperta Robertson, The Incrusting Cheilostomatous Bryozoa of the West Coast 



of North America, Univ. California Pub. IV, No. 5, p. 287, plate 19, fig. 41, 1908. 



(General bibliography.) 

 Schizoporella biaperta Osburn, Bryozoa of Tortugas Islands, Carnegie Inst. Wash., Pub.No. 



182, p. 207, 1914. (Regional bibliography.) 



