THE AMERICAN LOBSTER. 141 



l'AK.TI-OOLORED VARIETIES. 



Once in awhile a lobster is caught which exhibits a remarkably abnormal colora- 

 tion. A lobster which would weigh about 2 pounds was captured near Long Island, 

 Portland Harbor, about the year 1SSG. One half of the body was light yellow, clearly 

 defined up to the middle line of the back from the color of the other half, which was 

 bright red. There were no spots on the shell. This specimen was exhibited in Boston, 

 and afterwards sent to Professor Baird. 



De Kay mentions a similar case (51). He says: 



In .June, 1840, I saw in the Fulton Market a lobster which was of two colors, distinctly separated 

 by a medial line from the tip of the rostrum to the middle extremity of the plate of the tail. One side 

 of the body and all the members were of a light sky-blue, and the other of the usual olivaceous green. 



Mr. S. M. Johnsou informs me that it is not uncommon to get a lobster in which a 

 part of the body is pale red while the rest is normal in color, and that a few years ago 

 he had a specimen in which this difference in color was marked by the line running 

 through the middle of the back, and that even one-half of each u feeler" was light 

 and the other dark. 



Buckland (28) mentions the case of a half "albino" lobster, which he received in 

 May, 1868. He says : 



One side of the barrel was blue and the other was white. The bine turned red on boiline, but 

 the white did not There appeared to be no pigment in the white part of the shell. 



Boeck (20, p. 225) says that in 1868 he found a lobster near Haugesund, one half 

 of which was of a greenish-black and the other of a light-orange color, there being a 

 sharp and clearly defined line, which ran lengthwise and divided the shell into two 

 parts of equal area. This closely resembles the odd variations which we have just 

 noticed in the American species. 



Lovett (128) has described a number of color variations in lobsters from the 



island of Jersey. One which is particularly mentioned — a female with eggs was of 



a pale lavender color, with a mauve spot on the carapace and with bright blue claws. 

 The usual mottled markings on the sides of the thorax were rather indistinct. He 

 speaks also of having observed a full-grown female with eggs of a pale-reddish color, 

 with bright antenna?. 



Carrington and Lovett have described the great chromatic adaptability of the 

 common green crab, Carcinus mmias (35). 



Boeck says that the European lobster, taken near the mouths of fiords in Norway, 

 is lighter in color than is usual, while farther out to sea it becomes much darker. 



Malard thinks that these peculiar color variations are due to the loss of certain 

 pigments, in consequence of insufficient light, in the deep grottos or rocky crevices 

 where the lobsters may have lived. 



Protective coloration and chromatic adaptability to the immediate environment 

 are common to a large number of the Crustacea. It seems to be least observed in 

 the highest representatives, the Brachyura. According to Malard this chromatic 

 adaptation is effected either (1) chemically, by the modification of pigment under the 

 direct action of light, or (2) physiologically, by the action of pigment cells stimulated 

 by light, indirectly through the eyes and central nervous system. 



Pouchet has made some interesting observations (see 133) on the variations of color 

 in the common shrimp, Palaeinon. It was found to be most variable when 3 to 4 cm, in 



