THE NAUTILUS. 27 
grows, and sometimes Crepidula convexa which I found quite 
abundantly on Modulus floridanus, has the color and something of 
the corrugation of that shell, so that at first glance it appears to be 
merely a patch. 
What is the object of this singular species of imitation? I believe 
without exception it is a means of protection against the rapacity of 
boring molluscs ; one of the tricks which nature is constantly exhibit- 
ing by which the “survival of the fittest” is attained. The shells of 
the young oyster on the Cerithium, the Crepidula convexa on the 
Modulus, the Anomias and Crepidulas on the Pectens, were in every 
case thinner than those on which they grew, hence more liable to be 
pierced by carniverous molluscs—but by imitating the shells on 
which they lived they stood a better chance of deceiving their ene- 
mies, a better chance of self-preservation. Does this not look 
almost like intelligence, almost akin to what we call thought in man 
—like reason; like studying from cause to effect ? and I believe that 
such variation as this is often perhaps one of the first steps towards 
the formation of a new variety, a variation which if continued by 
circumstances fixes certain characters that define a species, and 
that these characters remain permanently—often after the causes 
which produced them have passed away. 
LIST OF SHELLS OF THE NEW JERSEY COAST SOUTH OF 
BRIGANTINE ISLAND. 
BY JOHN FORD. 
Ep. Navurizus, Dear Sir: 
As a list of the species of Mollusks found on the coast of 
New Jersey, South of Brigantine Island, may be of interest to your 
readers, I take the liberty of sending it. 
If any others can be added it would be a pleasure to hear 
of them. 
Yours truly, 
Joun Forp. 
Phila. June 15th, 1889. 
Anomia ephippium, Linn. 
Arca pexata, Say. 
Arca ponderosa, Say. ( Fossil.) 
Arca transversa, Say 
