Morse.] 



142 [April 5, 



velvety green color, was only taken upon wet mossy stones in the 

 bed of a mountain stream, where it was with difficulty detected. A 

 large, brown species (C. heros) was found chiefly on dead leaves in 

 forest paths ; and one which was never seen except on the wet mud 

 of salt marshes, was of a glossy olive so exactly the color of the mud 

 as only to be distinguished when the sun shone, by its shadow. 

 Where the sand beach was coralline and nearly white, I found a very 

 pale Cicindela; wherever it was volcanic and black, a dark species of 

 the same genus was sure to be met with." 



But little attention has been given to adaptive coloring among the 

 lower invertebrate animals. Darwin, in his last work on the "Descent 

 of Man" calls attention to the statements of Hseckel that the transpar- 

 ency of the Medusae and other floating animals is protective since 

 their glass-like appearance renders them invisible to their enemies, 

 though Wallace also alludes to this same feature (p. 258). Mr. 

 Edward Burgess informs me of a species of Acaleph, Polyclonia fron- 

 dosa, on the coast of Florida, which lives in the mud and is brown in 

 color. Darwin while admitting that the transparency of these animals 

 unquestionably aids them to escape the notice of their enemies, yet 

 doubts whether the color of Mollusks affords similar protection. He 

 says, "The colors do not appear in most cases to be of any use as a pro- 

 tection; they are probably the direct result, as in the lower classes, of 

 the nature of the tissues, the patterns and sculpture of the shell de- 

 pending on its manner of growth." Vol. I, p. 316. 



In glancing over our New England Mollusca, however, it seems 

 that we do have very clear evidences of protective adaptations 

 among them, not only in their form, but more particularly in their 

 color. It would seem strange indeed if this were not so since so 

 many species of Mollusca form an important portion of the food of 

 many fishes, 1 and also of certain species of birds. 



1 In an inlet near Salem the writer observed a school of minnows swimming 

 along the bottom and as they approached a certain point darting right and left in 

 great alarm. For some time the disturbing cause could not be found. On closer 

 examination, however, a Cottus was seen to open his large mouth and take in 

 several of the little fishes. The Cottus was so perfectly protected by its colors, 

 that it was only recognized when the capacious mouth opened, and only then were 

 the minnows alarmed. Just beyond in their track was a rusty tin fruit can, the 

 little tin remainiug on it reflecting the rays of the sun, and from this harmless 

 object they all turned affrightedly away. 



In this connection it would be interesting to inquire into the food of fishes in re- 

 spect to their colors. Those fishes feeding upon Mollusca would certainly not 

 require such protection for concealment as thoso living upon more active prey. 



