50 PEOCEEDIKTGS OP THE NATIONAL MUSEUM vol.72 



TREMOGASTERINA SPARSIPOROSA, new species 



Plate 33, Figure 3 



Description. — The zoarium is unilamellar. The zooecia are dis- 

 tinct, separated by a furrow at the bottom of which interjunctural 

 pores are visible, elongated, elliptical. The frontal is convex, finely 

 granular, perforated by four or five round, irregular, separated pores 

 and terminated by a cylindrical mucro more or less salient. The 

 apertura is elhptical, elongated, bordered by a thin peristome. The 

 avicularia are rather large, arranged between the aperture and in 

 the axis of a distal zooecium. They have a fragile pivot and their 

 beak is truncated. The ovicell is globular, somewhat transverse, 

 granular, not closed by the operculum, 



,, ^ A X f^a = 0.18-0.20 mm. 



Measurements. — Aperturei, „ ^^ ^ ^„ 



^ ua = 0.16-0.18 mm. 



„ . 1X2; = 0.75-0.90 mm. 



2°^^"^Mz. = 0.45-0.50 mm. 



Affinities. — The avicularia are large when they surmount a distal 

 zooecium; they are small in the contrary case. 



This new species differs from the recent Tremogasterina mucronata 

 Smitt, 1873, in its round and nonconcentrically arranged pores and 

 in its truncated avicularia. It differs from the recent Tremogasterina 

 ventricosa in its narrow aperture, in its much smaller zooecia, and in 

 its long and truncated avicularia. It differs from Tremogasterina 

 malleolus in its round, more numerous, and more scattered pores and 

 in its greater micrometric dimensions. The large avicularia measure 

 0.60 mm. by 0.26 mm. 



Occurrence. — Pliocene: Minnitimmi Creek, Bocas Island, Almi- 

 rante Bay, northwest Panama. 



Holotype. —C&t. No. 70865, U.S.N.M. 



Genus TREMOPORA Ortmann, 1890 



TREMOPORA RADICIFERA Hincks, 1881 



1889. Membranipora radicifera Jelly, Sj^nonymic Catalogue of Marine 

 Bryozoa, p. 162. (Bibliography.) 



We have found only a small specimen of this species but it is typi- 

 cal and well preserved. The zooecia are separated by the interjunc- 

 tural pores and on the dorsal there are small hydrostatic tuber- 

 osities. The occurrence of this species in the recent Gulf of Mexico 

 is quite probable. 



Occurrence. — Pliocene: Minnitimmi Creek, Bocas Island, Almi- 

 rante Bay, Panama. 



Distribution. — A widespread species of recent times and in the Mio- 

 cene of France, Austria, etc. 



