200 IOWA STUDIES IN NATURAL HISTORY 
species of that aristocratic genus. On account of its similarity 
to certain Pacific species, its synonomy in literature is long and 
confused. 
Although its geographical range is a wide one (Brazil to 
Hatteras), it is sparingly found. These were by far the finest 
specimens I have ever seen. They apparently lived wholly 
upon the densely packed bunches of a flat black bivalve, Melina 
(‘‘Perna’’) obliqua Lam. that occurs in quantity at about the 
low-tide mark on the wall. These poor clams must indeed have 
a hard time of it maintaining themselves against the rapacity of 
so active an enemy as the Murex. Besides these the wall offered 
some fine living examples of Tritonium pileare L. always show- 
ing the curious hairy epidermis of the genus. These seemed as 
ereedy as the Murex in browsing upon the helpless Perna. Ap- 
parently neither of these carnivorous species attacked their prey 
by boring through their shells, as is usually done by WNatica. 
Urosalpinx, and other predaceous gastropods. We were un- 
able to observe exactly the modus operandi; but the Murex 
seemed to surround the Perna, smothering 1+ m folds of its 
distended foot and probably forcing it through suffocation to 
open. 
Falmouth Harbor, just west of Engiish Harbor, yielded but 
little to the dredge, but its shores were richer in the ‘‘small 
fry.’’ By searching through the windrows of the flotsam of the 
beaches, we obtained a number of little Scalas, pyramidellids, 
rissoids, and some of the smaller auriculids. Always about us 
the many dead Phacoides, Lucina of several species, Yellina, 
Macoma, Cardium, Arca and other pelecypods gave evidence of 
no lack of molluscan inhabitants in the harbor, even if they did 
elude our dredge. Our best and most interesting results were 
from collecting at low tide among the rocks at the harbor en- 
trance. There quite a different assemblage of mollusks is to 
be found when once their hiding places could be detected. Two 
or three species of Thais (Purpura), Sistrum, Columbella 
mercatoria in quantity, Nitidula ‘catenata in little colonies 
Ultimus gibbosus with its mottled red mantle covering its lemon 
yellow shell, Cyprea cineria, Conus mus, Marginella avena, 
Pisana pusio, Leucozona cingulifera, Latirus wmfundibulum, 
two mitras, various limpets, chitons, ete.,— all were taken in 
