412 THE REPRODUCTIVE FUNCTIONS. 



tion is soon repaired; and if the whole animal be divided 

 into a great number of pieces, each fragment acquires, in a 

 short time, all the parts which are wanting to render it a 

 complete individual. The same phenomena are observed, 

 and nearly to the same extent, in the Plctnaria. The */s- 

 terias, the Jlctinia, and some of the lower species of Anne- 

 lida, as the Nats, are also capable of being multiplied by ar- 

 tificial divisions, each segment having the power of supply- 

 ing others, and containing within itself a kind of separate 

 and individual vitality. 



A power of more partial regeneration of mutilated parts 

 by new growths, which is very analogous to that of com- 

 plete reproduction, exists in the higher orders of animals, 

 though it does not extend to the entire formation of two in- 

 dividuals out of one. The claws, the feet, and the antennae 

 of the Crustacea, and the limbs of the JZrachnida, are re- 

 stored, when lost, by a fresh growth of these organs. If the 

 head of a Snail be amputated, the whole of that part of the 

 animal, including the telescopic eyes, and other organs of 

 sense, will be reproduced. Even among the Vertebrata we 

 find instances of these renovations of mutilated parts; as hap- 

 pens with respect to the fins of fishes: for Broussonet found 

 that in whatever direction they are cut, the edges easily 

 unite; and the rays themselves are reproduced, provided the 

 smallest part of their base has been left. The tails of Newts, 

 and of some species of Lizards, will grow again, if lost: and, 

 what is more remarkable, the eyes themselves, with all their 

 complex apparatus of coats and humours, will, if removed, 

 be replaced by the growth of new eyes as perfect as the for- 

 mer. We have seen that the teeth of Sharks and other 

 fishes are renewed with the utmost facility, when by acci- 

 cident they have been lost. Among Mammalia, similar 

 powers exist, although they are restricted within much nar- 

 rower limits; as is exemplified in the formation of new bones, 

 replacing those which have perished. When we advert to 

 the numberless instances of the reparation of injuries hap- 

 pening to various parts of our own frame, we have abun- 



