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bulletin of the bureau of fisheries. 
blood, which coagulates and forms a protective crust over the stump. In a short time a 
small white papilla, which represents the rudiment of the new limb, appears in the midst 
of the brown, hardened clot. This papilla continues to grow independently of the 
molting process, though covered with a cuticular membrane, until a miniature appendage 
is formed. The papilla lengthens, and gradually the constrictions which mark the 
future joints of the new limb make their appearance. At first colorless, the new 
appendage becomes bright, transparent red, with bluish pigment at the constrictions of 
the joints. In this stage the limb is surrounded by a thickening cuticle and soon ceases 
to increase in size until after the next molt. If autotomy occurs just after a molt, the 
appendage will reach a much greater size than if it happens a short time before, but 
within the limiting period referred to below. When the molt finally takes place the 
new stump becomes very much larger, and now resembles the normal appendage in all 
respects except size. With each succeeding molt the normal size is gradually attained. 
The large cheliped of the young lobster in the fifth stage may be regenerated in from 
15 to 18 days after a single ecdysis, or it may require a month’s time, during which the 
animal may pass two molts. The normal size, however, according to Emmel, is not 
attained until after the third molt. He also found that by the repeated removal of the 
same appendage in sixth to eighth stage lobsters the rate of growth in the mutilated 
limb was repeatedly reduced, but the experiment was not carried very far. This 
observer has also found that the thoracic legs will not begin to regenerate if removed 
immediately before a molt. The limit varies from 2 to 4 days in sixth to seventh stage 
lobsters. In more mature animals the limiting period is 16 days at its shortest duration. 
Accordingly, if accidents happen shortly before the molt, the animal must wait until this 
crisis is over before nature can give any attention to the restoration of the parts lost. 
Apparently in this case the energy required to renew the entire cuticular covering does 
not leave any surplus immediately available for the growth of new limbs and tissues. 
If the tips of the large chelipeds are clipped off, autotomy does not always or usually 
occur, and the limb is completely repaired after one molt. If the limb is injured below 
the propodus, it is usually cast off at the plane of fracture. 
The antennae are very liable to injury, particularly the delicate, sensitive flagella. 
Autotomy does not occur in these appendages, but regeneration may take place at any 
articulation in the flagellum or stalk. 
In the young the whip of the second antenna may be completely restored without 
a molt taking place, while in the adult one molt at least appears to be necessary for com- 
plete restoration. In the fifth stage lobster, already mentioned, the antennary flagellum 
was restored in about 15 days. This appears first as a papilla or bud, which becomes 
sickle-shaped and finally coiled so as to resemble a small spirally twisted red wax taper. 
The cuticle of the limbs in process of restoration must be elastic and capable of 
considerable distension, although the limit of this distensibility is, in most cases, soon 
reached. 
According to the studies of Miss Reed upon the process of regeneration in the crayfish 
(2J5), the membrane or the inner half of the double fold which remains after autotomy, 
and the blood cells beneath it serve to protect the end of the stump, but take no part in 
