760 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



PLATONEA CLAVATA, new species. 



Plnte 161, figs. 1, 2. 



-Description. -The zoarium incrusts shells and Orbitoid foraminifera ; it is 

 elongate, branching, with lobes in the form of a club. The fascicles are symmetri- 

 cally arranged, alternate or opposite, uniscrial, salient, little oblique. The tubes 

 are little visible, very little convex ; the peristome is thick, round or polygonal, 

 elevated almost vertically. The ovicell is quite large, globular, spread out between 

 the fascicles over the whole zoarial width. 



Diameter of the peristome 0.10-0.14 mm. 



Measurements. j D i stance between the fascicles 0.20^-0.24 mm. 1 



Our ovicelled specimen is not an excellent one and the oeciopore is not visible. 



Affinities. Most of the described Reptotubigera have no known ovicell. Their 

 comparison with our species is therefore absolutely useless. 



Occurrence. Vicksburgian (Marianna limestone) : Salt Mountain, 5 miles 

 south of Jackson, Alabama (rare). 



Cotypcs. Cat, No. 65441, U.S.N.M. 



PLATONEA LAMELLIFERA, new species. 



Plate 141. figs. 12-19. 



Description. The fragments of the zoarium are free, idmoneiform, very wide, 

 short, irregular with subelliptical transverse section. The fascicles are quite 

 salient, very close together, regular, alternated on each side of the median axis; 

 they are formed of three to eight zooecia. The zooecia are little visible, somewhat 

 convex ; the orifice is rectangular and transverse. The basal lamella is smooth ; it 

 bears salient lamellae as wide as the zoarium, the purpose of which is to remove 

 the latter from the substratum. The ovicell is lobate; it surrounds the fascicles 

 more or less completely and spreads over the whole surface of the zoarium; the 

 oeciostome is little salient and is adjacent to the first zooecium of a fascicle. 



Diameter of the tubes. _ _ 0.18 mm. 



Measurements. 



Distance between the fascicles.- _ 0.33 



mm. 



Width of the fascicles 0.18 mm. 



Zoarial width 3.00 mm. 



Variations. This species is idmoneiform, but the lobes are very short; they are 

 very thick at their extremity where the incompletely calcified zooecia are visible in 

 great number (fig. 14). Our specimens are somewhat altered; the basal lamella is 

 theoretically smooth (fig. 18), but the tubes are often visible (figs. 17, 19) by 

 chemical alteration. 



The dorsal lamellae rested on the substratum and strengthened the zoarium 

 which was spread out but very fragile and easily broken; their length is quite 

 variable (fig. 18). 



1 This is the distance between the peristomes and measured on the zoarial margins. To calculate the 

 visible zooecial length it is necessary to add the diameter of the peristome. 



