REGENERATION OF LOST ORGANS. 117 



that spiders have the power to cast off limbs at will. The first example 

 may have been a coincidence of the experiment with the full time for 

 moulting, when the old tegument was just ready to be cast and was at 

 once rejected through the sudden shock of the hot water plunge and the 

 violent death struggles. The second case may have been simply an actual 

 loss of a leg by handling. 



Dr. Heineken, however, seemed to have no doubt as to the power of 

 the animal to reject a leg. Moreover, he noted that the spiders which 

 Self Am- ^^^* °^ crushed limbs were "hunters;" those which retained 

 putation. *^^^"^ *^^® webmakers ; a difference for which he accounts by 

 supposing that the former, perhaps, have the strongest induce- 

 ment to the act, as an inert and powerless joint would be a greater 

 inconvenience to them than the loss of the whole limb. Furthermore 

 a webmaker, being of stationary habit, is less liable to accidents than the 

 himter, which is constantly on the move, and generally exposed. On this 

 point I may remark that I have often met Orbweavers with one, two, 

 four, and even five legs wanting, the result either of moulting mishaps, 

 or of adventures and battles with assailants of various sorts. It is not 

 uncommon to find males in this condition, a consequence of the unfa- 

 vorable attitude of females in courtship. One also occasionally finds 

 spiders with contorted legs which we would think might better be off 

 than on, did the aranead have the power of self amputation. Certainly, 

 these lost and wounded limbs did not prevent the spinning of snares, 

 for I have seen in two cases, at least, an Orbweaver with all the legs 

 wanting on one side weaving an efficient web. 



Mr. Francis R. Welsh writes me that he saw an Orbweaver, which was 

 probably Epeira insularis, that had lost seven of its feet (not legs) grasp 

 with its spinnerets a spiral of its web, underneath which it hung, and 

 hang thereto by the spinnerets only. It did not attach a dragline. It 

 afterwards hung and moved by bowing its legs over the spirals of its 

 web. A loss of this peculiar nature would probably have been occasioned 

 by impeded moulting, and illustrates not only the perils of this act, but 

 also the spider's power of adapting itself to extraordinary disadvantages. 



Blackwall has published several important papers on this subject. ^ But 

 foi- the most thorough and satisfactory studies of the regeneration of 

 excised members we are indebted to Mr. Waldemar Wagner. 

 .^ , This enthusiastic araneologist has pursued the entire histological 



development of certain organs, especially the legs, from the 

 moment of amputation until the appearance of the new limb, and I shall 

 undertake to interpret, substantially, the facts as recorded bj'^ him.^ 



' See, as already quoted, Trans. Linn. Soc, Vol. XVI., pages 482-84 ; Proceed. Brit. Assn. 

 Advc. Sci., Vol. XIV., pages 70-74, and Spid. Gt. Brit, and Ir., Introduction, page 7. 



- " La Regeneration des Organes Perdus chez les Araign^es." Voldemar Wagner. Bull, 

 d. 1. Soc. Imper. des Naturalistes de Moscow, 1887, No. 4. 



