426 BULLETIN 106, UNITED STATES NATIONAL, MUSEUM. 



mal border is straight or somewhat concave. The ovicell is globular, salient, cov- 

 ered with smaller tremopores than those of the frontal; it is hyperstomial and 

 always closed by the operculum. One of the lateral tremopores, near the aperture, 

 transforms itself into a small avicularium, simple, somewhat salient, and elliptical. 



f/w=0.12-0.14mm. . f Zs=0.55-0.60mm. 



Measurements. Aperture { 7 Zooecia , n .,. 



U<z=0.14-0.16 mm. 17,3=0.40 mm. 



Affinities. This species differs from Cydicopora longipora MacGillivray, 1882, 

 in its large tremopores which give it the aspect of a colander. 



It differs from Cydicopora fissurata in its much smaller dimensions and the 

 absence of elongated, lateral avicularia. 



Occurrence. Vicksburgian ("Chimney rock" member of Marianna lime- 

 stone) : One mile north of Monroeville, Alabama (very rare). 



Holotype.Cat. No. 64283, U.S.N.M. 



CYCLICOPORA SPONGIOPSIS De Gregorio, 1890. 



Plate 88, figs. 8-16. 



1890. Eschanr siinnriiopsis DE GKEGOKIO. Monographic de la Faune Eocenique de Alabama, 

 Annales Geologie et ele Taleontologie, Livr. 7, 8, p. 241, pi. 40, fig. 2. 



Description. The zoarium is unilamellar, cylindrical, hollow; it surrounds 

 the radicells of small algae. The zooecia are very little distinct, elongated, fusi- 

 form; the frontal is little convex, very thick and formed of a tremocyst with large 

 tubular pores resting on a very thin olocyst. The apertura is oval, at the base of 

 a deep peristomie ; the peristome is smooth, not salient, and bears from 1 to 4 simple 

 avicularia. The ovicell is hyperstomial. buried in the distal zooecia; it opens into 

 the peristomie, it is ornamented with large pores analogous to those of the frontal. 



rAa=0.20mm. . f 0=0.60-0.70 mm. 



Measurements. Apertura < 7 A1K Zooecia , n 



[te=0.1omm. 1/3=0.50 mm. 



Variations. There are occasionally some zooecia bordered by a prominent 

 thread (fig. 14). The number of small simple, peristomial avicularia is quite 

 variable; sometimes one (fig. 15) sometimes 3 or 4 (fig. 10). The frontal walls 

 are very thick and the tubules themselves have thick walls. In the transversal 

 sections (fig. 9) this same phenomenon is quite visible. The tangential section 

 (fig. 13) shows the large frontal tremopores and the black, sinuous lines of inter- 

 section with the olocyst. 



Affinities. This species resembles much the young zoaria of Porellacrasso paries 

 which surround also the small algae and their distinction is often quite difficult : it 

 differs from the latter in the complete absence of the median avicularium. 



It seems to us that this species resembles the figure given by De Gregorio of 

 his Eschara spongiopsis, but we have not been able to check this observation with 

 his type. 



Occurrence. Vicksburgian (Marianna limestone) : One mile north of Monroe- 

 ville, Alabama (very common) ; near Claiborne, Monroe County, Alabama (com- 

 mon). 



