24 PROCEEDINGS OP THE NATIONAL MUSEUM VOL.72 



what elongated, oval, sometimes ornamented with a very short 



gymnocyst. The mural rim is thin, salient. Its interior part is finely 



granular and slightly enlarged on the sides and at the hase; the termen 



is sharp. The opesium is oval and very finely denticulated. The 



vibraculum is small, elliptical, auriculated. The ovicell is endo- 



zooecial and very small. 



-,. ^ r\ • f^o = 0.20 mm. 



Measurements. — Opesmm^ , n i o r» i c 



^ lio = 0.12-0.16 mm. 



fZs = 0.36mm. 



Zooecia 7 _ _ . 



U2 = 0.24 mm. 



Variations. — On the rather small substratum the cells are neces- 

 sarily irregular and of variable dimensions. The ancestrula is sur- 

 rounded either by five cells and a vibraculum or by six cells and a 

 vibraculum, but they do not at all appear to result from budding of 

 this ancestrula. It is, moreover, difficult to trace the zooecial axes 

 on the convex specimens. 



Affinities. — This species is smaller than Vihracellina viator and 

 V. crassatina of the Philippines and V. capillaria Canu and Bassler, 

 1920. It is, on the contrary, larger than Vihracellina pusilla Canu 

 and Bassler, 1923, from the Pliocene of Florida. Its affinities are 

 rather vith Vibracellina simplex Canu and Bassler, 1923, from the 

 Miocene of Florida, but differs in its broader and more decorated 

 mural rim and in its denticulated opesium. 



Occurrence. — Pliocene : Minnitimmi Creek, Bocas Island, Almirante 

 Bay, Panama. 



Cotypes.—Csii. No. 70868, U.S.N.M. 



Genus ANTROPORA Norman, 1903 



ANTROPORA PUSTULATA, new species 



Plate 3, Figure 11; Plate 16, Figure 12 



Description. — The zoarium encrusts corals and fragments of shells. 

 The zooecia are distinct, separated by a furrow, elongated pyriform; 

 the gymnocyst is smooth, convex; the mural rim is little salient, 

 thin, pyriform; the cryptocyst is concave, smooth. The opesium is 

 elliptical, marginated, finely crenulated, ornamented with a distal, 

 oblique lamella, serving as a border to the deep opesium. The ovi- 

 cell is hyperstomial, independent of the distal zooecium. The mural 

 rim bears exteriorily four to six small hollow spines and two oblique 

 triangular avicularia. Irregular zooeciules, perforated, in the form 

 of small pustules, are arranged sporadically between the zooecia. 



Measurements. — Opesium] 7 ~n\A 



^ [io = 0.14 mm. 



Zooecial^^^^-^^-0-^^"'^- 

 "^^^^^^^2 = 0.35-0.45 mm. 



