600 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



SCHISMOPORA UMBONATA, new species. 



Plate 75, figs. 1-3. 



Description. The zoarium is discoidal. convex, incrusting; the marginal zooecia 

 are oriented; the central zooecia are heaped up. The superficial zooecia 

 are erect, salient, very oblique, orbicular; the frontal is smooth and prolonged 

 into a strong itmbo, deforming or hiding the apertura. The apertura bears a wide, 

 triangular, proximal rimule; it is little visible exteriorly. The deep zooecia are 

 little visible and are revealed only by their apertura; they have no umbo. The 

 marginal zooecia are oriented; their frontal is very convex and terminated by a 

 large umbo completely hiding the apertura. The incomplete zooecia are rare. 



\ha= 0.07mm. 

 \ Ja=QM mm 



Affinities. In its large umbo and its oriented" marginal zooecia this species 

 resembles f'ellepora pmnicosa Busk, 1852. It differs from it in the absence of a 

 visible avicularium on the umbo. 



It differs from Holoporclla fissurata, which is also surrounded by oriented 

 zooecia, in a larger umbo. in smaller dimensions, and the absence of areolae. 



Occurrence. Upper Jacksonian (Ocala limestone) : Alachua, Florida (very 

 rare) ; West bank Sepulga River, Escambia County, Alabama (rare). 



Holotype.C&t. No. 64211, U.S.N.M. 



SCHISMOPORA ORBICULARIS, new species. 



Plate 75, figs. 4-6. 



Description. The zoarium is unilamellar, little convex, incrusting algae. 

 orbicular, garnished inferiorly with an epitheca smooth or slightly striated con- 

 centrically. The superficial zooecia are buried, distinct, elliptical, almost always 

 oriented ; the frontal is smooth and little convex ; the apertura is oval, oblique with 

 a wide triangular sinus, and often accompanied by a small avicularium. The ovicell 

 reclines on the distal zooecia ; its orifice is at the level of the proximal border of the 

 peristomice. The deep zooecia have only their apertura visible. 



f A/? =0.11-0.12 mm. 



Measurements. Apertura < , 



mm. 



Affinities. The simplicity of structure of this species is remarkable. The 

 cumulate zooecia are rare and are at the very center of the zoarium. The zoarium 

 is manifest ty orbicular and can attain 7 millimeters in diameter; unfortunately, 

 we possess only the figured specimen. 



This species differs from Holoporclla, discus in its very numerous oriented 

 zooecia, in its apertura. which is smaller and of different form, and the absence of 

 perforations on the basal epitheca. 



In the determination of the Cellepores it is necessary to distrust the zoarial 

 resemblances. 



