THE AMERICAN LOBSTER. 
183 
to tlie primary egg-membrane that any attempt at its removal almost inevitably results 
in stripping off the blastoderm*with it. It is, however, soon absorbed, or at least 
detached, so that in the early egg-nauplius stages the shelling of the egg is quite an 
easy matter, yet when the egg-nauplius is fully developed the inner layer of the 
capsule invariably sticks to the tips of the antennse, which are usually torn off with 
its complete removal. 
At a stage closely following the egg-nauplius the embryo is inclosed by three dis- 
tinct membranes. I think it probable that the delicate inner cuticle, which can now 
be removed by the aid of hot water without injury to the parts, is a distinct structure 
from the blastodermic membrane just mentioned. The appendages at this time are 
gloved with a cuticular molt, evidently distinct from that which comes off with the egg- 
capsule when the animal is hatched. When eye pigment is formed these envelopes 
are very easily demonstrated, as seen in cut 20, plate F, where they have been distended 
by the prolonged action of picro-sulphuric acid. Up to this time it is therefore probable 
that at least three embryonic molts have occurred. Others follow during tlie.loug embry- 
onic life, and, as I have already shown, when the animal is about to hatch it is inclosed 
iu a cuticular molt which must be shed before it can enter upon its larval career. 
In the second molt, preceding the second larval stage, the delicate shell is cast 
entire, the only break being, as iu the later stages, along the margins of the inner fold 
of the carapace — that is, m the epimeral region of the branchial cavities and next 
the abdomen. The shed cuticula is transparent, colorless, and flexible, and contains 
little or no lime. The abdomen is usually withdrawn last, as is the case in adult life. 
The cast shell at the fourth molt, which precedes the fourth stage, contains a 
little lime, but no pigment. The fifth ecdysis, which ushers in the fifth stage, is 
more noteworthy. A larva of this period molted in a glass dish on my table in the 
forenoon of July 33, 1892, and was soon attacked by others in the dish and killed. The 
carapace is gradually elevated from behind, and the animal escapes through the open- 
ing thus formed. The calcareous shell, which is of a beautiful light-blue color, retaius 
its shape perfectly. The carapace, as early as the fourth stage, has a characteristic 
areolatiou (see figs. 113 and 115, plate 35) and is covered with short setae. There is a 
wide median stripe or band of absorption which branches into the cervical groove on 
either side and widens at the rostrum. The carapace can be easily split along this 
thin unpigmented area. 
The ecdysis of a lobster in the sixth stage, the color of which has already been 
described (hTo. 34, table 34), was observed under similar circumstances. On the 8th of 
August this lobster molted again while I was watching it-. At about 9.30 a. in., when 
first examined, the abdomen was drawn away from the thorax, showing a distended 
pink membrane which connects these parts of the shell. Fifteen minutes later the 
carapace was elevated, the pressure of the inclosed body swelling out the mem- 
branes slowly. At 10.24 a. m. the young lobster turned over on its side and in three 
minutes was out of its shell, about an hour having elapsed from the moment when 
the process, already begun, was observed. The eyes and cephalo- thoracic appendages 
are withdrawn first, and when these are free the animal slips away from the old shell, 
the abdomeu coming out last, as in the adult lobster. 
The color of the cast shell is blue, with some green and brown pigment on the 
tergal surfaces. Pigment is now gradually deposited in the outer calcified layer of the 
