LOST PARTS IN THE CRUSTACEA. 77 



rounding the situation of the germ. The greater number also 

 appeared to terminate at the circumference by means of blind ex- 

 tremities. A dark circular disc was seen at the extremity of 

 many of these cul-de-sacs, which had all the appearance of a ger- 

 minal spot. When these vessels were first seen, they were 

 thought to be connected with the reproductive gland alone, but 

 after farther observations, this appeared to be incorrect ; and, as 

 already mentioned, their relations are so extensive and compli- 

 cated, as to require much more time for their elucidation than I 

 have had since they came under my observation. It is evident, 

 however, they perform some important function in the economy 

 of the animal, but whether it is connected with the reproduction 

 of lost parts or not, is a question to be decided by future obser- 

 vation. 



Immediately on the limb being thrown off, a quantity of blood 

 escapes, which is soon stopped by the retraction of the vessels. 

 After this takes place, we see the small open foramen for the pas- 

 sage of the artery and nerve, which becomes closed almost im- 

 mediately by means of a slight film which spreads over the whole 

 of the exposed surface. When this surface is examined some 

 hours after the loss, we find that the small cavity of the foramen 

 is slightly filled up with a body resembling a nucleated cell. 

 This cell is the germ of the future leg, and very shortly encreases 

 in size, so as gradually to push out the film alluded to above, 

 which is now become a thick strong cicatrix. During the time 

 that this is going on, the whole of the exposed surface had be- 

 come tense and bulging, but this gradually decreases round the 

 circumference as the central nucleus encreases in size, which it 

 does at first longitudinally, and then transversely. As it en- 

 creases in size, the cicatrix, which still surrounds it as a sac, be- 

 comes thinner and thinner, until it bursts, when the limb, which 

 has hitherto been bent upon itself, becomes stretched out, and 

 has all the appearance of a perfect limb, except in size. 



In the lower Crustacea, and even in the lower Macroura, we 

 find the power of regeneration more extended ; a limb broken 

 off at any part of its phalanges will grow. The mode of repro- 

 duction in the lobster is peculiar, and differs from the higher 

 Crustacea. Instead of the young limb being folded upon itself, 



