298 TOWLE. [VOL. II. 



Dumeril (3), in his paper of 1867, in the course of other 

 observations, notes the fact that in an Axolotl the two anterior 

 limbs regenerated after injury. 



Wiedersheim, 1875 ( r > P- 95 )> found that the toes of Triton 

 cristatus will regenerate, while there is no regeneration of the 

 limbs in Proteus and Siren lacertina. 



Erber, 1876 (4, p. 34), notes regeneration of the feet of 

 Siren lacertina. 



Goette, 1879 (5), records the regeneration of a leg of Proteus 

 after a year and a half. Regeneration also occurs in Amphiuma 

 and Siren, in Triton cristatus, T. tacniatns, and their larvae. 



Weismann (9), in The Germ Plasm, 1893, says that the limbs 

 of Salamandra regenerate, while in Triton marmoratus regen- 

 eration is slight or absent. 



Barfurth (i), in 1894, reports regeneration of the feet and 

 digits of Triton tacniatus and Siredon pisciformis . This regener- 

 ation is normal or abnormal according to the plane and method 

 of the injury. 



I have experimented on the following forms, removing a fore 

 foot and a hind foot from different individuals of each species : 

 PletJicdon cincreus, Spelerpes ruber, S. giittolincatus, Desrnog- 

 natJtus ocJiropJiaea, Manculns quadridigitatns, Amblystonia 

 opacum, Diemyctylns viridesccns, AnipJiiuma means, and Nec- 

 tnrns inaculatus. Of these, all have regenerated. 1 The regen- 

 eration in Spelerpes, Desmognathus, Manculus, and Ambly- 

 stoma was comparatively rapid, and new limbs were well 

 formed in four months, though they were somewhat smaller 

 than the old limbs. Diemyctylus was slower in reaction, 

 while the first Necturus to show a distinct regenerated 

 stump did so only after eight months. Other individuals of 

 the same species showed no regeneration even at that time. 



I desire to thank Professor T. H. Morgan, under whose 

 direction this work was undertaken, for his kindly assistance 

 during its progress. 



BIOLOGICAL LABORATORY OF BRYN MAWR COLLEGE. 



1 Amphiuma means was observed for only eleven weeks. At that time regen- 

 eration was slight. The regenerated stump was not sectioned. 



