Beproduction 0/ Lost Farts in the Lobster. 371 



Tlie liinb is then ready to be set free, and the membrane 

 bursts. The new limb when liberated is about half the size 

 of the one lost. This process takes from three to six weeks 

 according to circumstances. With each successive moult the 

 new limb increases considerably in size, so that in time it 

 becomes similar in size to its fellow. According to Eeaumur, 

 the ambulatory limbs are produced in a similar manner, but 

 more slowly. " D'ailleurs dtant moins exposees a se casser, 

 parcequ'elles ne sont pas terminees par de grosses pinces, 

 elles se reproduisent et plus rarement, et ce qui est toiijours 

 a remarquer plus lentement." 



J. Couch, in a paper " On the process of Exuviation and 

 Growth of Crabs and Lobsters " (3), gives some notes on the 

 reproduction of lost limbs, which, however, are chiefly a 

 resume of Eeaumur's researches. 



The next important contribution to the subject was made 

 by H. D. S. Goodsir, in a paper read before the Wernerian 

 Society in December 1843 (4). Goodsir suggested a reason 

 why the lost limbs are usually reproduced from the first 

 phalanx. He says : " A small glandular-like body exists at 

 this spot in each of the limbs, which supplies the germs for 

 future legs. This body completely fills up the cavity of the 

 shell for the extent of about half an inch in length. The 

 microscopic structure of this glandular-like body is very 

 peculiar, consisting of a great number of large nucleated 

 cells, which are interspersed throughout a fibro-gelatinous 

 mass. A single branch of each of the great vessels, accom- 

 panied by a branch of nerve, runs through a small foramen 

 near the centre of this body, but there is no vestige either of 

 muscle or tendon, the attachment of which are at each ex- 

 tremity. In fact, this body is perfectly defined, and can be 

 turned out of the shell without being much injured. When 

 the limb is thrown off the blood-vessels and nerve retract, 

 thus leaving a small cavity in the new-made surface. It is 

 from this cavity that the germ of the future leg springs, and 

 it is first seen as a nucleated cell." 



In 1873, Chantran (5) published a series of observations 

 on the Crayfish, giving the time required for the reproduction 

 of lost parts in that species. He says that lost antenme are 



