84 
BULLETIN OF THE UNITED STATES FTSH COMMISSION. 
term u black lobster,” used by the fishermen on the coast of Maine, is not altogether 
inappropriate. The old shell is also brittle, owing to the absorption of organic matter, 
and if the carapace or large shield wliich covers the anterior half of the body is 
pressed between the fingers, it will sometimes split down the back in the longitudinal 
median furrow. In most cases the shell does not crack in this place unless artificially 
compressed. In the course of the preparation for the molt the lime salts of the 
shell are absorbed along the middle line of the carapace, leaving a narrow perfectly 
straight gutter, extending from the spine or rostrum to the posterior margin of the 
shield. The cliitiuous portion of the cuticle still remains, forming an inelastic hinge, 
on which the lateral halves of the carapace bend without breaking asunder. In the 
molted shell there is also a linear membranous area on either side of the rostrum. 
Absorption of the hard matter of the shell at these points tends to give greater latitude 
to the movements of the two halves of the carapace. If you examine a hard-shell 
lobster you will find in place of the median furrow a blue line, drawn as if with a fine 
pen and rule. Below this line the epidermic cells of the skin become so modified as to 
bring about the total absorption of the lime salts of the cuticle. In sections of the 
skin, however, it is difficult to detect any histological change in this linear area. 
Other areas of absorption, to be described hereafter, occur, which are of even greater 
importance to the success with which the lobster comes out of his old covering alive 
and whole. 
The period of uneasiness, which foreshadowed the molt and was very marked, 
ended in this lobster by its rolling over on its side, agitating its appendages, and 
bending its body in the shape of the letter V, the angle of the V coinciding with the 
gaping chink between the dorsal shield and “ tail.” Presently the old cuticle, holding 
these parts together and through which the new shell is seen, began to stretch, the 
wall of the body pressing against it with considerable force, and the hinder end of the 
shell being slowly lifted up, while its anterior part remained attached to the rest of 
the skeleton. The slow but sure pressure of the parts within cause an increasing 
tension in the yielding cuticular membrane, which finally bursts, revealing the brilliant 
colors of the new shell. The legs and other appendages are occasionally moved, but 
no marked convulsive movements are to be seen. The carapace has now become raised 
upward to an elevation of perhaps 2 inches behind, in consequence of which, the 
anterior end being fixed, the rostrum is bent downward and the animal now has a 
very singular appearance. 
When this much has been achieved the lobster becomes quiet for a few seconds 
and then resumes its task with renewed vigor. From this time on until free its 
muscles work intermittently. The doubled-up fore part of 'the body is with each effort 
of the animal more and more withdrawn from the old shell, and this implies the 
separation of the skin from the complicated linkwork of the internal skeleton and the 
freeing of the twenty-eight separate appendages, which are attached to this portion of 
the body, from their old cases, and at the same time the release of the muscles from the 
internal tendons of the large claws and other parts. The cuticular part of every ecto- 
dermic structure is stripped off. This exoskeleton folded up to fit such a complicated 
mold is in reality a continuous structure, and from the method of its regeneration the 
sloughing of one part necessitates the shedding of the whole. 
The carapace is now elevated to such an extent behind that the rostrum is 
directed obliquely downward and backward. The lobster is still lying in comparative 
