LIFE HISTORY OF THE BLUE CRAB. 107 
In the process of regeneration a very small, white papilla, or protuberance, first 
forms in the end of the old stump. This papilla enlarges and becomes a sort of thin- 
walled sac in which the new appendage is formed. As the sac becomes larger the new 
appendage can be seen folded up within it. At molting the sac is thrown off with the 
old shell, and the new limb appears in its normal shape, but is smaller than the corre- 
sponding member of its pair. At subsequent moltings it increases in its relative pro- 
portions and eventually attains the normal size, unless the loss occurred only a molting 
or two preceding the acquisition of adult size. In that case the new appendage remains 
smaller than its fellow. Many adult crabs are found in which one claw is smaller than 
the other or both claws are below normal size. Such an undersized claw is termed by 
crabbers a ‘‘jew claw,” i. e., reduced or ‘‘jewed down.”’ 
As an example of autotomy, the record of a crab which was kept under observation 
will be presented. A female crab, No. 9 of Table B, 1.687 inches in width and with the 
left claw missing, was placed in a small cage in the water on June 1. No papilla or 
limb bud had begun to form. This crab was kept under observation until July 21. 
The growth at the moltings which occurred during this time is recorded in the following 
table: 
TABLE E. 
Lengthof claw,includ- | Width of claw in 
ing entire arm. widest place. 
Date of molting. Width. 
Right. Left. Right. Left. 
Inches. Inches. Inches. Inch. Inch. 
I tremerc seen ete facie creas cee riere aidwig'e  atajsbiaeistc siete dlobiars » sis's'o(a[s 1.687 1.625 (») o. 18 (0) 
FUME eet ee ce oisie ces ae tanate alate eins «in mv’ ein e's wieyaiaipi e's pie\s vie a hippie mistalel 2-125 2.250 1-75 -25 o. 18 
FROIN oy otee es orninw 5 nlo:n'o)s is nlnjnie n'e10'e(niais'0ininln sininipio niniololnia='alnin’n(>o.a afaia 2.750 2-930 1.87 +35 +31 
SUR ea Ret teta fe nein ole vip ae wiainisisiety siptciainte alain s'a'w\nlala nidiniajeta‘e\siniala.v- aiaie\yidio.a 3-750 3-500 3-50 +50 +43 
SEAM MNESS otne a ctoietada ac csleitaictaeebtdee <eicin claisemawiess sciae ed 2-063 1-875 3-50 +32 +43 
@ Placed in cage. > Claw missing. ¢ Gain in 5 moltings or 51 days from time claw was lost. 
It was necessary to close the experiment at this point. The left claw had practically 
reached the size of the right in three moltings, or in about 51 days from the time when 
it was lost. Plate LI, figure 24, represents the successive molts of the claws during 
the course of the experiment. 
In the juvenile crab the completion of the process of regeneration never occurs 
except at the time of molting, although limb buds may be seen forming before this. 
The presence of a fairly large-sized limb bud is a sign that the crab is approaching or 
is already in the peeler state. If, as has been stated, molting does not occur after the 
crab has attained maturity and if regeneration does not occur except through molting, 
the adult crab can not renew cast-off appendages. Further research is necessary to 
clear up this point. Adult crabs cast off the appendages apparently as freely as do 
the juveniles. Whether they regenerate these or not, the author is not in a position 
to state. An adult female with limb buds has never been seen by the author or by 
