NORTH AMERICAN EARLY TERTIARY BRYOZOA. 223 



Affinities. This species differs from Floridina lagunculu in its larger micro- 

 metric dimensions (Lz=0.50 mm. and not 0.40 mm), in its nearly always trifoliate 

 opesium. and in its large and rounded opesiular openings. It is smaller than 

 Flo rid ina on.ydi fata. 



Occurrence. Middle Jacksonian : AVilmington, North Carolina (common) ; 

 near Lenuds Ferry, South Carolina (common) ; Baldock, Barnwell County, 

 South Carolina (common) ; 3^ miles south of Perry, Georgia (rare) ; 3^ miles 

 north of Grovania, Georgia (rare) ; H miles northeast of Lily, Dooly County, 

 Georgia (rare). 



Upper Jacksonian (Ocala limestone) : Bainbridge, Georgia (rare) ; 1J miles 

 above Bainbridge, Georgia (rare). 



Vicksburgian (Marianna limestone) : Salt Mountain, 5 miles south of Jackson, 

 Alabama. 



Vicksburgian (Byram marl) : Byram, Mississippi (rare). 



Habitat. Smitt's original specimens' were obtained in the waters of Florida, 

 where the species ranges in depth from 29 to 44 fathoms. 



Plesiotypes.C&t. No. 63984, U.S.N.M. 



FLORIDINA LAGUNCULA, new species. 

 Plate 36, figs. 1-6. 



Description. The zoarium is free, unilamellar, creeping over algae, or incrust- 

 ing stones, shells, or bryozoa. The zooecia are a little elongated, distinct; confluent 

 through their mural rims; the cryptocyst is shallow, oblique, directed toward 

 the opesium. very finely granular; the mural run is projecting in front, convex, 

 separated from the cryptocyst. The opesium is limited to the elliptical, trans- 

 verse opercular portion; the two opesial processes are quite salient and are situated 

 above the polypidian convexity, which is thus little apparent. The onychocel- 

 larium is elliptical, elongated, larger than a zooecium; its opesium is oval, divided 

 into two parts, a lower one large and nearly round, and a distal one narrow and 

 linear. 



Measurements. Opesium f/?=0.10-0.r2 mm. . tLz=QAQmm. 



Zooecium ' 



(including opesiules)Ufl=0.20 mm. ' U3=0.3Q-0.35 mm. 



fZon=0.5 

 Onvchocellarium ,' , 



[ton=0.33 



Variations. In tangential sections the zooecial walls appear very thin (fig. 

 5). In the interior, the opesium is trifoliate or has the aspect of Thalamopordla 

 or of Steganoporella (fig. 6). On the lower face of the zoarium, the zooecia are 

 elongated, hexagonal, convex, and bear a projecting hydrostatic tuberosity (fig. 3). 



The opesiules placed between the polypidian convexity and the opesial processes 

 are hardly visible because they are thus perpendicular to the zooecial plane. But 

 with the reduction of the processes they become visible in the form of rounded 

 lateral openings (fig. 4). 



In some specimens from the Vicksburgian the proximal border of the onycho- 

 rellarian opesium is straight and the opesium itself is oval. 



