NORTH AMERICAN EARLY TERTIARY BRYOZOA. 325 



It differs from Beisselina forata, which is also provided with large frontal 

 pores, in its larger zooecial and zoarial dimensions. 



Ocffiirrence. Lower Jacksonian (Moodys marl) : Jackson, Mississippi (rare). 

 Holotype.C&i. No. 64038, U.S.N.M. 



BEISSELINA IMPLICATA. new species. 



Plate 44, figs. \-A. 



Description. The zoarium is an Eschara with fronds linear and elongated. 

 The zooecia are hardly distinct; the frontal bears 2 to 4 pores, an ascopore, and a 

 small, salient avicularium; the peristome is salient; the peristomice is orbicular. 



(Ae=0.06-0.07mm. 

 Measurements. Peristomice , A _ A nfT 



\lpe-O.OQ~0.07 mm. 



Affinities. This species, complicated in appearance, differs from Reisselina 

 f>'u7la in its little distinct zooecia, in its smaller frontal pores, and in the smaller 

 diameter of its peristomice (0.07 mm. instead of 0.11 mm.). 



Figure 3 perhaps represents a distinct species, but it is the only specimen 

 found. 



In the geologic column this is the last Beisselina observed. We have no knowl- 

 edge of the genus in the Miocene or Pliocene. 



The small salient avicularium is far from being constant and many specimens 

 are deprived of it. 



Occurrence. Upper Jacksonian (Ocala limestone) : Alachua. Florida (com- 

 mon) : 9 miles north of Ocala, Florida (rare) ; 14 miles above Bainbridge, Georgia 

 (rare). 



Cotypes.Cat. Nos. 64039, 64040, U.S.N.M. 



Family HIPPOTHOIDAE Levinsen. 1909. 



The zooecia become calcified from behind in successive zones forward, leaving 

 at the surface more or less salient lines, the lines of growth, and are furnished 

 with a variable number of dietellae. 



The genera of this family are as follows: 



Hippothoa Lamouroux, 1821. 



CJwrizopora Hincks, 1880. 



Trypostega Levinsen, 1909. 



Haplopoma Levinsen, 1909. 



Dacryopora Lang, 1914. 



This family, in spite of its exterior appearances, is not a natural one. The 

 larva of Chorizopora is not identical with that of Hippothoa and Haplopoma. 

 The ovicell of Trypostega is not like the gonoecia of other genera. We have 

 therefore not given a general table for the family, but have indicated the zoological 

 bibliography for each genus. 



