August 16, 1901.] 



SCIENCE. 



241 



position where they can seldom be injured, 

 and I have never found them absent or 

 injured in crabs caught in their natural 

 environment. The soft abdomen is pro- 

 tected by the snail's shell. At the end of 

 the abdomen the last pair of abdominal 

 appendages serve as anchors to hold the 

 crab in the shell. These appendages are 

 large and very hard, and can seldom be in- 

 jured unless the abdomen itself is broken, 

 and under these circumstances the crab 

 dies. Yet if these appendages are cut off 

 they regenerate perfectly, and after a single 

 moult can not be distinguished from normal 

 ones. 



The more anterior abdominal appendages 

 are present only on one side of the adult, 

 although they are present on both sides 

 of the larva, and to judge from a compari- 

 son with other Crustacea these appendages 

 have degenerated completely on one side, 

 and have become rudimentary in the male, 

 even on the side on which they are present. 

 These appendages regenerate if they are 

 cut off. In the female the appendages are 

 used to carry the eggs, and are, therefore, 

 of use. They also have a similar power 

 of regeneration. The maxillae and maxilli- 

 peds of the hermit-crab have also the power 

 of regeneration, as have also the two pairs 

 of antennse, and the eyes. 



In other decapod Crustacea also it has 

 been shown that the power of regeneration 

 of the appendages is well developed. It has 

 been long known that the crayfish and the 

 lobster can regenerate lost parts. The first 

 pair of legs, or chelae, in these forms has a 

 breaking-joint, at which the leg can be 

 thrown off, yet in the crayfish I have seen 

 that if the leg is cut off inside of the break- 

 ing-joint it will regenerate. The four pairs 

 of walking legs do not possess a breaking- 

 joint, but may be thrown off in some cases 

 at a corresponding level. They regenerate 

 from this level, as well as nearer the body 

 and further beyond this region. Pizibram 



has recently shown that, in a number of 

 Crustacea, regeneration of the appendages 

 takes place, even when the entire leg is ex- 

 tirpated as completely as possible. 



Newport has shown that the myriapods 

 can regenerate their legs, and it is known 

 that several forms have the power of break- 

 ing off their legs in a definite region at the 

 base if the legs are injured, and I have 

 observed in Cermatia forceps that this take» 

 place even when the animal is thrown into 

 a killing fluid. Newport (1844) has also 

 shown that when the legs of a caterpillar 

 are cut off new ones regenerate during the 

 pupa stage. It has been long known* that 

 the legs of mantis can regenerate, and Bor- 

 dage, who has recently examined the ques- 

 tion more fully, has shown that a breaking- 

 joint is present at the base of the leg. The 

 tarsus of the cockroach also regenerates, 

 producing only four, instead of the five, 

 characteristic segments. f 



A number of writers have recorded the 

 regeneration of the legs of spiders.'! Schultz, 

 who has recently examined more thoroughly 

 the regeneration of the legs in some spiders, 

 finds that the leg is renewed if cut off at 

 any level. He removed the leg most often 

 at the metatarsus, but also at the tibia, and 

 generally between two joints. In some 

 cases the leg was cut off at the coxa, at 

 which level it is generally found to be lost 

 under natural conditions. Wagner ob- 

 served in tarantula that when the leg is re- 

 moved at any other place than at the coxa 

 the animal brings the wounded leg to its 

 jaws, and bites it off down to the coxa. In 

 the Epeiridce, that Schultz chiefly made use 

 of, this never happened. He observed, 



* See Newport and Scudder. 



t Brindley, '97. 



jLepelletur, Nouveau Bulletin de la Socicte philoma- 

 tique, 1813, Tome III., page 254. 



Heincken, Zool. Journal, 1829, Tome IV., page 

 284. (Also for insects, ibid., page 294.) 



Miiller, 3Ianual de Physiol., Tome I., page 30. 



Wagner, W., Bull. Soc. Imp., Naiurel., Moscow, '87. 



