310 MARINE INVERTEBRATES 
barrier and maintain themselves very successfully at Martha’s 
Vineyard and in Long Island Sound. Some of the species whose 
natural habitat is south of Cape Cod are also to be found north 
of that point, but they do not reach their full development in the 
colder waters of Massachusetts Bay. 
The long stretch of coast-line from Cape Cod to Florida is 
easily susceptible of faunal subdivision at Hatteras, below which 
locality a decided mixture of Antillean species is apparent. Be- 
tween Long Island Sound and Hatteras the littoral molluscan 
fauna is disappointing to the collector, for the number of species 
is relatively small, and few even of these are entitled to any claims 
to beauty of shell. The nature of this coast, virtually a great 
sweep of exposed sand-beach, is not conducive to a varied or rich 
fauna. But if this portion of the transatlantic province is lack- 
ing in interest to the shell-collector, it is anything but disappoint- 
ing to the army of men employed in the oyster- and clam-fishery. 
It is only within this faunal area that the American oyster, Ostrea 
virginica, the best of the edible shell-fish, finds its natural home, 
and here the oyster-culture is most extensively carried on. 
After storms the Jersey beaches are frequently strewn with 
Mactra, Tagelus, Arca, and Ensis ; in more sheltered places Fulgur 
and Polynices (Lunatia) are commonly met. These may be ac- 
cepted as the most characteristic genera of this province. 
Just south of Cape Hatteras an observer is struck with the 
sudden change in the appearance of the shells on the beach. 
Cardium, Cassis, Dolium, Arca, and Cancellaria at once suggest 
the West Indies. About the vicinity of Hatteras the Gulf Stream 
approaches very near the land, bringing with its warm waters 
many wanderers from tropical homes. From Beaufort to Florida 
there is another long stretch of exposed and shifting sand-beach, 
which offers a scant return to the collector of mollusks. 
THE CARIBBEAN PROVINCE 
When Florida is reached a new world is opened to the natural- 
ist, for there a better acquaintance is made with the great Carib- 
bean province, which, extending from Florida to the northern 
shores of South America, embraces all the Bahamas, the West 
