NORTH AMERICAN EARLY TERTIARY BRYOZOA. 605 



of the two usually has a small projection from the base or columc'Ha" (Waters, 

 1909). Spines. 16-18 tentacles. 



Genotype. HoloporcUa (Cellepord) JescostUsii Savigny-Audouin, 18-26. 



Range. Claibornian Recent. 



HOLOPORELLA ORBICULIFERA, new species. 



Plate 16, figs. 10-15. 



Description. The zoarium is small, massive, convex, incrusting shells. The 

 superficial zooecia are prominent, oi-bicular, separated; the frontal is smooth gar- 

 nished with a very few areolae; it is terminated by a very fragile aviculiferous 

 beak. The apertura is somewhat elongated, finely crenulated; the anter is semi- 

 lunar and is separated from a concave poster by two small cardelles placed very 

 low ; the peristome is very thin and bears two large spines. The ovicell is recum- 

 bent, hyperstomial, transverse. The deep zooecia have a deep peristomie; they 

 have neither spines nor avicularia. The incomplete zooecia are accompanied by a 

 small elliptical or round avicularium with pivot. 



f Aa 0.09 mm. 

 Measurements. Apertura 7 no 



lz=0.06mm. 



Variations. Usually the beak is broken and leaves a broad cicatrix on the 

 frontal. The very small zoarium does not permit of good photography of the 

 characters. The thin section shows some more or less large pores between the 

 zooecia; they are irregular and do not appear to correspond to a definite organ. 

 Some zooecia have a small, triangular upper chamber; this is the cavity of the 

 aviculiferous beak (fig. 15). The walls are formed of scattered olocystal elements 



(fig- 11). 



Affinities. In the smallness of the zoarium and in its zooecial aspect this 

 species approaches somewhat Iloloporella separata. It differs from it in its im- 

 bedded zooecia without pedunculate avicularia. 



Occurrence. Claibornian (Gosport.sand) : Claiborne, Alabama (rare) ; 1 mile 

 west of Eockville, Clarke County, Alabama (rare). 



Cotypes.Czt. No. 63859, U.S.N.M. 



HOLOPORELLA FISSURATA, new species. 



Tlate 76, figs. -1-G. 



Description. The zoarium forms small, convex masses on shells or on the 

 radicells of algae; on oysters it is surrounded by a large zone of oriented zooecia. 

 The superficial zooecia are salient, round, erect; the frontal is smooth, surrounded 

 by four to seven large areolae; it is terminated by a pointed mucro deforming the 

 apertura and bearing an oral avicularium, rather large and with a bar. The aper- 

 tura is semilunar; the anter is large and the poster is concave: the peristome is very 

 thin and very little salient and bears two large, symmetrical spines. The ovicell 

 is salient, transverse, recumbent; it opens by a very large opening above' the aper- 

 tura ; it bears a long arched fissure. The oriented zooecia are marginal ; they are 



