THE AMERICAN LOBSTER. 175 



green. Bright yellow-green areas are noticeable on the abdominal terga as before, and 

 upon the hinder portion of the carapace. There is some brown pigment on the large 

 chehe and tail Ian. In the fourth variety (fig. 36), the abdomen and chelae are rich 

 reddish brown, with light peacock-green on the terga of the abdominal rings, as is 

 commonly seen, and on the carapace next to the abdomen. The rest of the carapace is 

 greenish brown. In this and all earlier stages the color of the carapace is partly due 

 to that of the internal organs, especially to the alimentary tract and gastric glands. 



The following notes illustrate the changes which individual larvae undergo, with 

 reference to molting and surrounding conditions. A fourth larva raised from the egg, 

 when examined on July 13, was decidedly bluish. The whole animal was quite trans- 

 lucent, the heart and yellowish "liver" showing plainly through the shell. The claws 

 and body were sky-blue, due, as in the first larva, to the blood pigment. The brown 

 and yellow chromatophores were contracted to such an extent as to have no appreciable 

 effect upon the general color pattern. Two days later the carapace was greenish and 

 the chela? dark brown. On July 17 the colors were deeper; on the 19th the general 

 cast of color was dark bluish-green; reddish-brown on the abdomen and chela?. On 

 July 21, when the animal was nearly ready to molt, the carapace was bluish-green, the 

 abdomen and chela? brownish-red. Four days later, July 25, this animal molted to the 

 fifth stage. The fifth larva was dark olive, tinged with brown on the abdomen and chehe. 



A larva which molted July 11 to the fourth stage was pale, and apparently 

 almost devoid of pigment. The internal organs were plainly visible. There was a 

 delicate wash of brown on the abdomen, tail-fan, and chela?. The microscope showed 

 that the closed chromatophores were very small. 



Another larva, 13.1 mm. long, which was raised from the egg, had on July 6 the 

 usual mixture of brown and green pigments. On July 15 the animal was very dark 

 brown, excepting the carapace, which had a metallic green luster. The large chela? 

 are tipped with white or cream color, and there is a large light patch ou the outer side 

 of the hinder end of the exopoclite of the uropod. Fainter and smaller whitish areas 

 occur on the pleura of the first abdominal ring. This larva molted about August 3 to 

 the fifth stage; color, reddish-brown. 



Barely is a larva seen which is reddish-orauge, the blue and brown pigments 

 being almost completely obscured. The pigments of the eye are similar to those of 

 the earlier stages. 



In a larva of 14 mm. long, observed July 25, the carapace was of the usual greenish- 

 brown cast, with three light-greenish spots on each side — a very small spot behind 

 the eye, a smaller one below this, and a larger one farther back below the cervical 

 groove. These are the first traces of very characteristic areas, which I shall call 

 "tendon marks," upon the skeleton of all later stages, and mark the places where 

 certain muscles are attached to the integument. The significance of these color 

 changes will be considered later on. (See p. 135.) 



A fourth larva, which was caught at the surface near the Fish Commission wharf 

 on a very bright day (July 25, 1891), was similar in color to some of those already 

 described. The thorax was green, brightest posteriorly; the chela? and abdomen dark 

 reddish-brown; a brilliant light-green area appeared on the tergum of the third and 

 fourth abdominal segments. 



On August 10 I examined a number of lobsters in the fourth, fifth, and sixth 

 stages, which had been kept in glass jars and fed upon meat. Many of these were so 



