NO. XII. 



THF MODE OF REPRODUCTION OF LOST PARTS IN TEE 

 CRUSTACEA. 



That all the species of Crustacea have the power of regene- 

 rating parts of their body which have been accidentally lost, is a 

 fact which has been long known. The particular manner in 

 which these new parts are developed, and also the organ from 

 which the germ of the new part is derived, has never yet been 

 sufficiently examined, or properly explained. 



If one or more of the last phalanges of the leg of a common 

 crab be seriously injured, the animal instantly throws off the re- 

 maining parts of the limb close to the body. It has the power 

 of doing so, apparently for two purposes ; to save the excessive 

 flow of blood which always takes place at the first wound, and to 

 lay bare the organ which is to reproduce the future limb. As 

 soon as the injured limb has been thrown off the bleeding stops, 

 the reason of which will be explained hereafter ; but if the ani- 

 mal is unable, from weakness or other causes, to effect this, the 

 haemorrhage proceeds to a fatal termination. 



It is apparently in the organs of locomotion only that the power 

 of reproduction resides. That it does not do so in all parts of 

 the body in the higher Crustacea, at least is proved by experi- 

 ment, and is also apparent from the circumstance of many species 

 being obtained with the body and other parts very much maimed, 

 and which have to all appearance been so for a considerable 



