ART. 14 FOSSIL AND EECEiSTT BEYOZOA CAIsTU AND BASSLEE 47 



When the calcification is not too intense, four spines are visible on 

 the very thin peristome; the latter is altogether detached from the 

 pleurocyst which covers the frontal; the latter phenomenon is, more- 

 over, visible on all the species of the genus. 



The ectocyst is visible on the inner face of the colonies; it is not 

 on the exterior face, but the specimens dredged alive have a beauti- 

 ful clear white color. 



On the fossil specimens the small cribriform area is little apparent 

 and often closed; the small spines of the peristome are still visible. 



Affinities. — This species differs from Tremogasterina mucronata 

 Smitt, 1873, in the constant absence of the oral mucro and in the 

 absence of three scattered pores on the frontal. It differs from Tre- 

 mogasterina horrida Canu and Bassler, 1923, from the Miocene of Flor- 

 ida in its larger dimensions, in its smaller cribriform area, in its 

 smaller inter junctural pores, and in its unilamellar zoarium. The 

 three species are very closely related. 



Occurrence. — Albatross Station D. 2639, Straits of Florida; 25° 04' 

 50'' N.; 80° 15' 10" W.; 56 fms.; coral sand. 

 Fowey Light, 15 miles south of Miami, Fla., 40 fms. 

 Pliocene : Minnitimmi Creek, Bocas Island, Almirante 

 Bay, Panama. 

 . Cotypes.— Cat. Nos. 7603, 70863, U.S.N.M. 



TREMOGASTERINA VENTRICOSA, new species 



Plate 13, Figures 1, 2 



Description. — The zoarium encrusts nuUipores. The zooecia are 



distinct, separated by a line of interjunctural pores, very large, ven- 



tricose ; the frontal is convex, rugose, and often bears a large mucro 



in the vicinity of the aperture; a large orbicular concavity contains 



a variable number of small reniform pores arranged concentrically. 



The aperture is suborbicular, very little elongated; the peristome is 



very thin and accompanied by five beautiful hollow spines arranged 



above it. The ovicell is globular, very large, rugose. The avicularia 



are elliptical, very salient; their orifice is triangular with a complete 



pivot. 



,, J A i. [^a = 0.25 mm. 



Measurements. — Apertures , ^ ^„ 



LZ£i=0.22 mm. 



ry . fZs = 1.00 mm. 

 Zooecia 7 _ __ 



[lz = 0.oo mm. 



, . 1 . iLav = 0.45 mm. 

 Avicularia 7 „ „^ 



[Lav = O.SO mm. 



Variations. — This is a very variable species. The mucro is very 



inconstant, often absent; the number of small pores of the frontal 



area varies from one zooecium to another; the beak of the avicula- 



rium is very pointed or rounded ; next to transverse zooecia there are 



