a 
re ~ = — —— 
NO. 5 FORAMINIFERA FROM TRINIDAD—SAUNDERS 5 
an adult stage of very irregularly arranged chambers. Wall: Thin, 
of coarse sand grains with almost no cement; in the late chambers 
of very irregular forms, large quartz grains may be incorporated. An 
inner “chitinous” layer is present. Surface rough. Color brown. 
Chambers: In planispiral tests, normally six to seven inflated cham- 
bers in the last whorl increasing fairly rapidly in size; where an addi- 
tional irregular stage is present, the later chambers are inflated, of 
variable size, and added at random. Sutures: Radial, depressed in 
the planispiral portion of the test. Apertures: Single or multiple 
areal apertures in chambers of the last whorl of planispiral tests. In 
tests with irregular adult chambers the aperture is single or multiple 
and areal in the planispiral early part, normally multiple (usually from 
two to six openings) in irregular later development. Size: Planispiral 
form of figure 2, maximum diameter 0.45 mm., approximate thickness 
0.23 mm. Irregular form of figure 5, length approximately 0.7 mm. 
Irregular form of figure 6, length 0.64 mm., maximum thickness ap- 
proximately 0.37 mm. 
Locality —Figured hypotypes (U.S.N.M. Nos. P5093 to P5099) 
from sample J.S. 65, Maracas Bay River, north coast of Trinidad. 
Distribution—Trochamminita irregularis Cushman and Bronni- 
mann emend. Saunders occurs in great numbers in the Maracas Bay 
River on the north coast of Trinidad; elsewhere on the island its 
distribution seems to be sporadic. The rich locality in Maracas Bay 
(sample J.S. 65) is in a shallow tributary drain of the Maracas Bay 
River. The drain runs parallel to the sea a short distance behind the 
beach, from which it is separated by a screen of mangroves and coco- 
nut palms. 
Remarks.—The very well preserved material used in the present 
study has shown that the original description is incorrect. The main 
difference lies in the discovery of all types of test form, from regular 
planispiral tests with one or more areal apertures in the last chamber 
(pl. 2, fig. 2) to forms with only a small planispiral or very slightly 
trochospiral early stage followed by irregular chambers in which areal 
apertures are usually multiple (pl. 2, figs. 6-8). Commonly found are 
intermediate types which are largely planispiral but have one or two 
final chambers added out of the original plane of coiling, and nor- 
mally have multiple apertures in the last chamber (pl. 2, figs. 3, 4). 
All stages may be found in the same sample. The final, highly irregu- 
lar forms are close to the figures of the holotype and paratypes of 
Trochamminita irregularis given by Cushman and Bronnimann 
(1948a, pl. 4, figs. 1-3). However, Cushman and Bronnimann did 
not record the presence of multiple apertures. 
