180 BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 



„ . , ^ fi^a = 0.13mm. 



Measurements. — Apertura , „ , _ 



^ l(a = 0.15mm. 



Affinities. — The general aspect recalls a little that of Holoporella janthina 

 Smitt, 1872. It differs from it in the presence of areolar pores, much scattered, 

 and in the presence of the large oral mucro. The oral mucro does not exist on 

 the young zooecia. 



Occurrence. — Pleistocene: Mount Hope, Panama Canal Zone (very rare). 



Holotype.—Ca,t. No. 68710, U.S.N.M. 



Genus SCfflSMOPORA MacGillivray. 1888. 



(For description, see Bulletin 106, U. S. National Museum, p. 598.) 



SCHISMOPORA BREVINCISA, new species. 



Plate 32, figs. 11-13. 



Description. — ^The zoarium incrusts shells. The zooecia' are erect and heaped 



at the center and oriented on the margin ; the frontal is formed by a granular pleuro- 



cyst surrounded by some large areolar pores. The apertura is oblique, semicircular, 



with a very short, rounded rimule. The interzooecial avicularium is elongate, 



elliptical; its opesium is very large, and its beak is quite rounded. 



,, , . ^ f^a = 0.15 mm. 



Measurements. — ^Apertura, ... 



^ |ia = 0.16 mm. 



Variations.— The adventitions organs are quite irregular. Besides the large 

 interzooecial avicularium without pivot, there are still some much smaller avicularia, 

 almost orbicular or somewhat elongate and provided with a pivot. The medium 

 umbo is always very short when it exists; it limits then an irregular slit which is 

 a false rimule. The marginal zooecia are much elongated and sometimes almost 

 cyclindrical. 



Affinities. — This species differs from Discopora verruculata Smitt, 1872, in the 

 absence of a transverse avicularium on the frontal. 



Occurrence. — Pliocene (Caloosahatchee marl) : Shell Creek, De Soto County, 

 Florida (common). 



Cotypes.— Cat. No. 68711, U.S.N.M. 



SCHISMOPOKA ABRUPTA, new species. 



Plate 40, figs. 10, 11. 



Description. — The zoarium incrusts shells. The zooecia are indistinct, erect ; 

 the frontal is smooth and terminated by a mucro very little salient. The apertura 

 is semicircular, with a wide rimule short and rounded. The ovicell is deeply 

 embedded between the adjacent zooecia; it is transverse, smooth, convex ; it is widely 

 open in a locella limited by the medium umbo, and it can not be closed by the oper- 

 culum. There are numerous, small, triangular avicularia with pivot disseminated 

 between the apertures. 



^a = 0.15 mm. 

 la = 0.15 mm. 



Affinities. — The apertura is rarely visible; it is always deeply embedded at the 

 base of a sort of locella. The small avicularia are sometimes more developed; 

 they elongate, become lanceolate, and lose their pivot. In spite of the lack of 

 precision in its exterior characters this species is not very difficult to determine, 

 thanks to the very special appearance of its avicularia. 



Occurrence. — Pleistocene: Santa Barbara, California (rare). 



Cotypes.—C&t. No. 68712, U.S.N.M. 



Measurements. — Apertura 



