20 PROCEEDINGS OF THE NATIONAL. MUSEUM vol. 80 



Holotype of vofnety.—lJ.^.'^M. No. 73816 (Cushman Coll. No. 

 15306), from Upper Cretaceous of pit at Lizard Springs, near 

 Guayaguayare, southeastern Trinidad, British West Indies. 



Remarks. — This variety is very common in the Trinidad material 

 but is not well developed in the Upper Cretaceous of the United 

 States, although it does occur in Mexico. 



CLAVULINA CHITINOSA, new species 



Plate 5, Figubes 9-11 



Desofiption. — Test elongate, slender, the early triserial portion 

 often being of slightly greater diameter than the later uniserial por- 

 tion ; chambers numerous, fairly distinct ; sutures distinct, depressed, 

 especially in the last-formed part of the uniserial portion; wall 

 almost entirely chitinous, clear, and translucent, very smooth; aper- 

 ture terminal, with a slight neck and lij). Length, up to 1 ; diameter, 

 up to 0.3 mm. 



^oZ(?^2//;e.— U.S.N.M. No. 73817 (Cushman Coll. No. 15315), from 

 Upper Cretaceous of pit at Lizard Springs, near Guayaguayare, 

 southeastern Trinidad, British West Indies. 



Remarks. — This is a peculiar form evidently representing deep- 

 water conditions, where the wall of the test becomes almost entirely 

 pure chitin. As a result of this type of wall, specimens are usually 

 much distorted, but the figures will give the general appearance of 

 the species. 



Family SILICINIDAE 

 Genus RZEHAKINA Cushman, 1927 



RZEHAKINA EPIGONA (Rzehak) var. LATA Cushman and Jarvis 



Plate 6, Figures 1 a, h 



Rzehakina epigona (Rzehak) var. lata Cushman and .Tarvis, Coutr. Cushman 

 Lab. Foram. Res., vol. 4, p. 93, pi. 13, figs. 11 a, I, 1928. 



Test differing from the typical in the broader, nearly circular form 

 and the much more prominent appearance of the last coil, foirming 

 almost a rounded carina about the periphery. This is the commonest 

 form in the collection. Some young specimens show the early coils 

 making a flattened test before the lateral thickenings are added. 



This variety is more rounded and much larger than the form found 

 in the Velasco shale of Mexico. In addition to the Lizard Springs 

 locality, it is abundant in the Hobson clay from San Fernando. 

 Trinidad. 



