NORTH AMERICAN EARLY TERTIARY BRYOZOA. 1'29 



curved; finely striated. The opesium is of the same form as the zooecia. The 

 avicularium is interzooecial, small, oblique, rounded or pointed; two lateral den- 

 ticles indicate the axis of rotation of the mandible. The ovicell is globular, in- 

 distinct, smooth, rarely carinated. 



T f rj fZs=0.50 imn. 



Measurement*. Zooecia , 



[/s=0.2o-0.30 mm. 



Affinities. The differences between this species and Ellis ina (Reptoftustrella) 

 oralis D'Orbigny, 1852, are quite insignificant, except that its dimensions are larger 

 and the ovicell is almost never carinated. 



It differs from Ellisina (Semifliwtrella) rhomboidalis D'Orbigny, 1852, in 

 which the micrometric measurements are almost identical although slightly smaller, 

 in the much less lozenge shape of the zooecia. 



Ellisina brevis differs from E. laxa not only in its much smaller dimensions, 

 but in its elongated zooecia which are less protuberant in aspect. In these very 

 simple forms, the micrometric dimensions are the only constant characters of 

 differentiation. 



Occurrence. Middle Jacksonian: Near Lenuds Ferry, South Carolina (rare) ; 

 Eutaw Springs, South Carolina (rare). 



Upper Jacksonian (Ocala limestone) : H miles above Bainbridge, Georgia 

 (rare). 



CAt. Xos. 63896. 63S9T, U.S.N.M. 



ELLISINA PROFUNDA MacGillivray, 1895. 



Plate 25, fig. 3. 



1S95. Membranipora profunda MACGILLIVRAY, A Monograph of the Tertiary Polyzoa of Vic- 

 toria, Transactions of the Royal Society of Victoria, vol. 4, p. 36, pi. 4. fig. 14; 

 pi. S, tig. 2. 



190S. Memlraniitora profunda CANU, Iconographie cles Bryozoaires fossiles de 1'Argentine, 

 Annies del Museo National de Buenos Aires, vol. 17, p. 258, pi. 2, fig. 11. 



The external aspect, the position, the direction of the avicnlaria, and the micro- 

 metric measurements exactly alike, all indicate or appear to indicate the identity 

 of the American specimens with Membranipova, profunda MacGillivray, 1895. 

 However, our unique specimen from near Lenuds Ferry, South Carolina, presents 

 a remarkable peculiarity not described by the Australian author and which has not 

 been observed 011 the specimen from Patagonia. In the interior of each zooeciuin 

 there is a kind of double partial mural rim; distally two irregular pores separate 

 the two mural rims. This arrangement greatly simulates the structure in the 

 interior of the zooecia of Chaperia. The study of this interesting feature remains 

 to be made when more numerous specimens have been found. The avicularium is 

 sometimes developed in the interior of the distal zooecium. 



Occurrence. Lower Jacksonian (Moodys marl) : Jackson, Mississippi (very 

 rare). 



Middle Jacksonian: Near Lenuds Ferry, South Carolina (very rare). 



55899 19 Bull. 106 - 9 



