ART. 14 FOKAMINIFERA PEOM TRINIDAD — CUSHMAN AND JARVIS 19 



Test large, elongate, sides parallel for most of their length, slightly 

 (.'ontracted at each end, entire test triangular in transverse section, 

 the periphery rounded, the sides concave; chambers numerous, the 

 early ones triserial, later ones forming the larger part of the test, 

 uniserial; sutures very slightly if at all depressed, somewhat indis- 

 tinct; wall coarsely arenaceous but very smoothly finished; aperture 

 terminal, circular, with a very slight neck. 



This sjDecies is apparently very abundant in the Gulf Coastal Cre- 

 taceous of the United States. The original figures show only the 

 megalospheric form, which has nearly parallel sides and compara- 

 tively few chambers. The microspheric form is much larger and 

 increases rapidly in diameter toward the apertural end, but usually 

 occurs with the megalospheric form. The surface is usually smoothly 

 finished, and quite different from the following species. It was 

 originally described from the Upper Cretaceous, Velasco shale of 

 Mexico and is common in the Cretaceous of Texas, Arkansas, and 

 Tennessee but rare in this deeper-water material from Trinidad. 



CLAVULINA ASPERA Cushman 



Plate 5, Figueb 4 



Clavulina trilatera Cushman var. aspera Cushman, Bull. Amer. Assoc. Petr. 

 Geol., vol. 10, p. 589, pi. 17, fig. 3, 1926. — Cushman and Jarvis, Contr. 

 Cushman Lab. Foram. Res., vol. 4, p. 93, pi. 13, fig. 5, 1928. — White, Journ. 

 Pal., vol. 2, p. 315, pi. 42, fig. 14, 1928. 



This species was originally described as a variety of Clavulina tri- 

 latera. A further study of these forms from Mexico, Trinidad, and 

 the general Gulf Coastal region of the United States seems to show 

 that the two are distinct species. G. aspera always seems to have a 

 rough surface, and in the typical form the sides are nearly parallel, 

 although they may be somewhat more flaring in the microspheric 

 form. Such specimens are rare in Trinidad, but the following variety 

 is much more common. 



CLAVULINA ASPERA Cushman WHITEI, new variety 



Plate 5, Figures 6-8 



Clavulina trilatera White (not Cushman), Journ. Pal., vol. 2, p. 315, pi. 42, 

 fig. 13, 1928. 



Description. — Differs from the typical in the shape of the test, 

 which in the megalospheric form has the triangular portion confined 

 to the early portion of the test after which a series of rounded cham- 

 bers of nearly uniform size is developed, in the microspheric form, 

 with the triangular form continued throughout or becoming quad- 

 rangular in section, test increasing gradually in diameter to the 

 apertural end; wall roughened. 



