Charles D. and Mary Waux Walcott Research Fund 
TROCHAMMINIDAE AND CERTAIN 
LITUOLIDAE (FORAMINIFERA) FROM 
THE RECENT BRACKISH-WATER 
SEDIMENTS OF TRINIDAD, 
BRITISH WEST INDIES 
By JOHN B. SAUNDERS 
Trinidad Leaseholds, Lid., 
Pointe-a-Pierre, Trinidad, B.W.I. 
(Wit Four PLateEs) 
INTRODUCTION 
The study of foraminiferal material obtained during a comprehen- 
sive program of sampling in the brackish-water environment around 
the coasts of Trinidad, B.W.I., has brought to light a number of 
taxonomic problems. This paper describes all the Recent brackish- 
water Trochamminidae known from Trinidad, some Lituolidae requir- 
ing emendation, and others not previously recorded from Trinidad. 
In 1948, Cushman and Bronnimann published two papers (1948a, 
1948b) on the brackish-water Foraminifera of Trinidad. These papers 
were pioneers in this branch of the study of Recent faunas. Since 
then, many papers written in North America have added considerably 
to the knowledge of brackish-water faunas there. 
In the inshore, brackish-water environment in Trinidad, salinities 
are always lower than in the open sea as precipitation is higher than 
evaporation and streams continue to bring down fresh water into the 
marsh areas throughout the year. The range of salinities is higher 
than in the open sea, especially in river estuaries. Temperatures are 
exceedingly variable, as mud banks may be under only a very shallow 
water cover at low tide. The percentage of dissolved oxygen is also 
variable, depending on whether fresh water is being introduced or 
whether semistagnant conditions exist. 
The calcareous forms that can flourish in the coastal swamps and 
river estuaries belong mainly to the genera Rotalia and Criboel- 
phidium. The arenaceous forms are described herein, except for 
SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 134, NO. 5 
