742 Scientific Proceedings, Royal Dublin Society. 
Although this apparatus allows the very minute bodies sus- 
pended in the surface-water to escape, it affords beautiful samples 
of Foraminifera, Diatoms, Crustacea, Infusoria, Peridiness, &e. ; 
and we were rewarded by soon finding specimens of the bodies we 
were looking for—the coccoliths. These occurred, not free; for 
they are so minute as to easily pass through the meshes of the 
finer gauze, nor yet aggregated in coccospheres, as Wallich! 
described having found them in shoal-water off the south coast of 
England, but implanted on an ameeboid protozoan, resembling a 
Difflugia in appearance. 
This protozoan occurs in great quantities in the surface-water 
off the coast of Dublin and Killiney Bays. It is urn-shaped 
(fig. 8), and narrows suddenly to the aperture which is surrounded 
with a collar of hyaline siliceous material. Lobose pseudopodia are 
extruded through this collar in life, and its internal edge is orna- 
mented by a circlet of minute teeth, standing up from it obliquely. 
The urn-shaped covering of the organism is covered with thin 
flat grains of sand fitted into each other with nicety. Among 
these grains, fragments of sponge spicules may occasionally be 
seen, and, besides these, an odd coccolith was often observed 
implanted in the test. In fact, we estimated that about 25 per 
cent. of these Difflugia possess one or two coccoliths. 
Fig. 8 shows a coccolith, i situ, on the Difflugia. The 
coccolith frequently occupies a position on the shoulder of the 
protozoan, or it may be closer to the collar. More rarely it is 
found on the converging conical end of the test. 
This find encouraged us to pursue our search. For it appeared 
probable that the coccoliths had been acquired by the protozoan in 
the same manner as the grains of sand, and that, like the latter, 
they were floating free, suspended in the sea-water. If this 
surmise as to the relations of the two organisms was correct, it 
must follow that examination of the most minute solid constituents 
of the sea-water would reveal the presence of free coccoliths in 
considerable numbers. 
To test this question, two litres of sea-water were allowed to 
stand twenty-four hours in a tall, narrow jar; the upper portion 
was then siphoned off, leaving about 200 c.cs. of the lower 
1 Ann. and Mag. of Nat. Hist., 1868. 
