40 G PROCEEDINGS OF THE SCIENTIFIC ASSOCIATION.. 
probably the difficulty of inducing laborers to go and! 
remain there was even a more serious matter than any 
other, for the situation not only cuts them off from gossip 
and relaxation with their fellows, but has an evil repute 
for the prevalence of marsh fever. This malarious condi- 
tion is likely to exist in those bays [till the value of land in 
the colony so rises in course of time, and communications 
bo improve as to induce the owners to drain off the stag- 
nant waters. 
Here I found 19 species of bivalves, and 23 of univalves,, 
among which were the following : Cardita dactylus, Area 
squamosa, Mjtilus brazilianus, Area reticulata, A. occiden- 
talis. I was presented with a specimen of Pecten nodosus, 
one of Pinna ramulosa, and a large and porfect Area occiden- 
talis. The univalves contained a good many large shells, 
most of them dull or worn specimens ; Turbo tuberosa, Bulla 
ampulla, Triton sp., Conus musicus, Imperator digitatus, 
Cyproea exanthema (called in the Virgin Is'lands the ground 
sea shell, from a murmur as of the distant surf when the 
phell is held close to the ear.) My guide, when along this 
coast, on the 21st November and 4th December last, had 
brought back 43 species of bivalves, and 57 of univalves 
from Las Cuevas alone, and be declares, that on each 
occasion he has been here, he has found the beach much 
altered, and with different shells. 
