LIFE HISTORY OF THE BLUE CRAB. 105 
outer segments of the swimming legs. In a day or two this line becomes white, and 
the crab is known as a green, fat, or snot crab. Within three or four days the line 
becomes pink or red. (See Frontispiece, upper small figure at left.) It is formed by 
the edge of the segment of the leg, which has become loose from the old shell about 
it and has produced a bright fresh one, which is visible through the thin, outer old 
shell. A crab bearing the pink or red line, sign, or ring will molt within two or three 
days and is known as a peeler or, more rarely, a sluffer. A set of fine wrinkles also 
makes its appearance on the blue skin between the wrist and upper arm of the claw. 
A reddish color begins to appear at the margins of the segments of the abdomen. The 
carapace, or black shell, and the top shell of the abdomen are naturally not continuous, 
and, when the moment of molting is at hand, the carapace begins to be lifted up 
slightly, so that a gap appears between it and the abdomen. Then, on the under 
surface of the carapace, a crack appears in the shell at each end of the gap just men- 
tioned. As the carapace rises the crack on each side lengthens, passes below the 
spines, and extends nearly to the mouth. The posterior part of the body begins 
to protrude through the gap thus made. A crab in such a condition is known as a 
“buster” (Pl. LU, fig. 25). At this time it usually lies motionless, but can swim quite 
actively if disturbed. The remainder of the molting process requires only a few 
minutes, usually about 15. The carapace is lifted higher, the swimming legs begin 
to be withdrawn by rhythmic throbbing movements, and the body protrudes more 
and more from the shell (Pl. LII, fig. 26). The claws are the last to be with- 
drawn from the old shell, and, as they are large, some difficulty is involved in pulling 
them through the narrow arms of the claws. To obviate this, a roughly triangular 
portion of the shell of the large segment of the arm breaks along the outer side and 
rises up like a flap (Frontispiece, figure at lower left, and Pl. LII, figs. 26 and 27). The 
opening thus made extends along the arm to the body, and thus the natural opening 
for the connection of the muscles of the arm with the body is enlarged. Through this 
the large claw is drawn (Pl. LII, fig. 28). Immediately after molting is completed 
the skin is soft and wrinkled, and the spines are curved forward (Pl. LII, fig. 27). 
Although the crab is flabby and apparently helpless, it is capable of walking or swim- 
ming slowly if disturbed. 
The spines soon become extended, and the shell fills out and begins to harden. A 
female crab was taken while in the buster condition and was placed in an aquarium in 
the laboratory, where it was allowed to complete the molting process. This crab 
measured 3.5 inches in width before molting. At 10.15 a. m., the instant after molting 
was completed, and at later intervals, the crab was measured. ‘he results are sum- 
marized as follows: 
Date. Condition. Hour. Width. 
| 
Inches. 
pte ace ye, th series «cpa Site as Stare vino sbpihrs w Medea’ « wierd es «Sia tp rads inte f A CLORERMOIEING, . Sexy io] +210 Aa Ee week 3-500 
petted atin Gann aaa aoe edn as elation? apa snts’ ksi tin doebesaf nie Giarcls cleipie enue n= | SILSCRELOLCEGLS, oe acts caies 10.15 &.M..... 4.000 
a taetecctateees aidlersiviata’sidieni<tareleieitete <elarieretecteie"e's' enc ss E[ Ge kielna at niece hae o nytt ate mE ke Diet eEL eG oes 4.312 
ERA ble SaMeleciats slvid.c ou tlds bec kpapey whle'e ch ons ceisiedcclasiet s ican eRe sldcv ak ac eect! Qi itcesn eed 4-437 
Vtabe Med ip Wetdd » uae deinge « clpeiv at «. sineldde «dup .o« + allmare Baty brmepereeyiye «iy jocsstereeeereeereeade es 2-801P. TEL. 5 ssn 4-500 
Seeds ee oinieiaiateleta dias ictus cic vise. Sab iny'cis.cisic.suair.eie isis’ o vigease cles ota | (2) 9.308.M...,.. 4-500 
Sane NUM ete aestaein resets ck cacti neat cc cence ycsrecet cscs ste es (c) RSS MER Sera a ere 4-500 
@ Approximately. > Shell leathery, ‘“‘buckram.” ¢ Shell nearly hard. 
