THE FORAMINIFERA OF PORTO RICO. 
By JAMES M. FLINT, 
Medical Director , U. S. Navy. 
The foraminifera belong- to the subking-dom Protozoa, class Rhizopoda; that is to 
say, they are among- the simplest forms of animal life, consisting- of a minute mass of 
protoplasm, or an aggregation of such masses, without organs or tissues, capable 
of protruding any part of the body in the shape of line threads, which How together 
whenever they touch, forming a granular network. They are aquatic, mostly marine 
animals, generally microscopic in size, and are inclosed in shells or “tests” composed 
either of calcium carbonate-secreted by the animal, or of available foreign material, such 
as mud, sand, sponge spicules, or dead shells, united by a calcareous cement. A few 
species are pelagic, but the greater number of species live at the bottom of the sea. 
The shells of recent foraminifera are found almost everywhere on the ocean bed, 
the exceptions being in the polar seas, and in the abysmal depths below about 2,500 
fathoms where the shells seem to be dissolved in the dense waters. As fossils they 
are widely distributed and of great geological significance, since they are the source of 
all the chalk and much of the limestone all over the world. These calcareous strata 
are in process of formation at the present day, the same as in past geological ages. 
There is but little on record regarding West Indian foraminifera. Few dredgings 
have been made in that vicinity, and fewer have been studied and reported. The 
Challenger records one dredging off Culebra Island, in 390 fathoms of water, from 
which 177 species of foraminifera were identified, showing that foraminifera are 
very plentiful in these waters in depths below the coral and above the abysses. The 
Albatross also found foraminifera in great variety and quantity along the northwest 
coast of Cuba. 
The Fish TIawk expedition to Porto Rico obtained foraminifera by shore col- 
lecting at Ensenada Honda, Caballo Blanco, and Mayaguez, and with the dredge or 
tangle at the following seven stations: 
Station 
No. 
Locality. 
Depth. 
Bottom. 
Instrument. 
0053 
0079 
0080 
6086 
6091 
6092 
6093 
San Juan Harbor, NW. angle of Morro Castle 1 mile 
Off St. Thomas, Sail Rock W. by N. i N. 6 miles 
Off St. Thomas, Sail Rock NW. 1 W. 4 miles 
Off Culebra, Punta Mula light-house SW. 1 S. 8J miles 
OfF Vieques, Culebritas light-house NE. i N. 10 "dies 
Off Vieques Island, Culebritas light-house NE. § E. 7± miles 
Off Culebra, Culebritas light-house NE. 51 miles 
Fathoms. 
4 to 7j 
20 23 
20 
141 
15 
16 
15 
Finesand. 
Coral 
do 
Coral, sand 
Coral 
do 
do .... 
Dredge. 
Tangle. 
Dredge. 
Do. 
Tangle. 
Do. 
Do. 
As will be seen, all the dredgings were in quite shoal water, with coral or coral 
sand at the bottom. The quantity of material gathered was generally quite small, 
yielding few foraminifera. Station 6093 furnished only 7 individuals, Ensenada 
Honda 6, Caballo Blanco 3, and Mayaguez only 2 or 3 exceedingly minute ones. 
2d— F. C. B. 1900—27 415 
