76 SHALLOW-WATER FORAMINIFERA OF TORTUGAS REGION. 
This species, originally described by d’Orbigny as common in 
shallow water off Cuba and Jamaica, is widely distributed in the 
West Indian region and occurs in considerable numbers in the 
Tortugas collection. It seems to be widely distributed across the Indo- 
Pacific, reaching its best development in waters less than 30 fathoms 
in warm seas. . There is a certain amount of variation in the number 
and prominence of the cost, but in general its characters are very 
constant. 
Triloculina quadrilateralis d’Orbigny. 
Triloculina quadrilateralis d’Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 1839, 
‘‘Foraminiféres,”’ p. 173, pl. 9, figs. 14 to 16.—Cushman, Proc. U. S. Nat. Mus., 
vol. 59, 1921, p. 71, fig. 11 (in text). 
Test somewhat longer than broad, in the adult the exterior composed of 
3 chambers, generally quadrangular in outline, the periphery slightly convex, 
but the angles acute and projecting, sides concave; wall with numerous fine, 
incised short lines; aperture oblong, with a single elongate tooth, projecting 
slightly above the outline of the aperture. 
Length of the Tortugas specimens up to 0.65 mm. 
D’Orbigny described this species from Cuba, and I found speci- 
mens from the north coast of Jamaica which were evidently the 
same species. It has been found at most of the stations in the 
Tortugas region, and therefore is probably widely distributed in the 
general West Indian region in comparatively shallow water. The 
quadrilateral condition is only developed in the adult, the younger 
chambers often being simply carinate or sharply angled. In the 
adult specimens the aperture may become much more elongate 
than is shown in d’Orbigny’s figure and the lip extends out somewhat 
beyond the periphery of the test. 
Triloculina bicarinata d’Orbigny. 
(Plate 12, Figure 7.) 
Triloculina bicarinata d’Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 1839, “ Forami- 
niféres,’’ p. 158, pl. 10, figs. 18 to 20. 
Test longer than broad, triloculine,. typically with the chambers with a 
truncate periphery, the angles somewhat extended; chambers distinct; sutures 
somewhat depressed; surface ornamented by reticulations both on the sides 
and on the outer angles; aperture elongate, with a definite thin lip, slightly 
everted, tooth elongate, narrow, extending above the outline of the aperture. 
Length of the Tortugas specimens up to 1.4 mm. 
This species, which d’Orbigny described from Cuba, may be dis- 
tinguished from the preceding, not only by the shape of the test, 
but also by the difference in reticulations. In 7’. bicarinata the 
reticulations are as shown by d’Orbigny, more or less rectangular, 
and much coarser than in 7’. carinata. In that species the retic- 
ulations are much smaller and are either rounded or elliptical and 
much more regularly placed. 
