192 BULLETIN OF THE BUREAU OF FISHERIES. 



and in the exoskeletons of crustaceans generally. MacMunn is of the opinion that they 

 are "built up in the digestive gland and carried in the blood current to be deposited in 

 other parts of the body." If this is true, it would not be remarkable if the color of the 

 animal were affected by the nature of its food, yet this does not seem to be often the case. 

 Following the classification of Bateson (^ig) we distinguish between (a) variations 

 in colors themselves, and (b) variations in color patterns. The variation in colors, 

 which Bateson calls "substantive variations," may be the result of a physical or chemical 

 change, and has no vital significance. The different colors themselves are further 

 liable to different discontinuous variations, as when crustaceans occasionally lay bright, 

 golden-yellow eggs, while the normal color is dark green. 



The following substantive variations have been met with: (i) Blue lobsters, in 

 which the prevailing color is blue; (2) red lobsters, which are pure red or reddish yellow; 

 (3) cream-colored lobsters, characterized by the almost entire absence of color; and we 

 should also add (4) black lobsters, to include possible cases of melanism, where the 

 colors are extremely dark. A specimen of this kind was reported to me at Beal Island, 

 near West Jonesport, Me., where a fisherman recently captured, in 3 fathoms of water 

 among the eelgrass, a lobster about 6 or 7 inches long with moderately hard shell and 

 almost jet black. He supposed at first that it was covered with coal tar. It did not 

 appear to be preparing to molt. Malard speaks of meeting with cases of melanism in 

 crabs, where in consequence of a lesion of the skin the animal becomes entirely black. 



Changes in color pattern are more elusive. There are (i) the normal variety, in 

 which the upper part of the body is mottled with green, blue, and cream color; (2) spotted 

 or "calico" lobsters, the coloration of which is a bold pattern of green and light-yellowish 

 or cream-colored spots; (3) pied or parti-colored varieties, in which the contrast of 

 tints is abnormally pronounced. This may perhaps be better classed under substantive 

 variation. The changes are due apparently to vital or physiological causes, which have 

 at least no adaptational significance." 



There is no sexual color variation in the lobster, and such substantive variations 

 as the eggs undergo are not of an adaptive character. The freshly laid egg is dark green, 

 sometimes almost black, due to the presence of dissolved lipochromogens. Occasionally 

 the ova are nearly pea-green, grayish-green, or greenish-straw color, but the golden- 

 yellow variation, so striking in some of the snapping shrimps, has never been observed 

 in the lobster. 



If the eggs are treated with hot water, alcohol, or other killing reagents, the green 

 lipochromogen is quickly converted into red lipochrome. When the water is heated 

 gradually, the red color appears slowly, and it is interesting to observe that if these 

 red eggs are now plunged into cold water the green color is restored. This change may 

 be somewhat analogous to the breaking up and reconstruction of the blue compound of 

 of starch and iodine upon the successive application of heat and cold, and to the varia- 

 tion in color which sometimes appears in the living animal at the time of the molt. 



a For fuller account of red living lobsters and other color variations, with illustrations, see z4g. 



