REGENERATION OF THE LEG OB AMPHIUMA 



MEANS. 



T. H. MORGAN. 



My object in studying the regeneration of the limbs of Ain- 

 phiuma means was to discover whether the limbs, which appear 

 to be of so little use to the animal as organs of locomotion, have 

 the power to- regenerate as have the limbs of other urodele 

 amphibia. 



The first amphiuma that I obtained (in 1900) was a large in- 

 dividual, and after several months had begun to regenerate, but 

 died as the result of an accident before regeneration had gone 

 very far. 1 The next individual that I was able to procure was 

 also large, but escaped before regeneration had gone any farther 

 than in the last case. Two smaller individuals have been kept 

 for more than a year (from March 21, 1901, to May 3, 1902). 

 The following account applies to them. Each had a fore-leg 

 and hind-leg of opposite sides cut off through the upper portion 

 of the leg. In the course of several weeks a knob of new tissue 

 appeared which continued to elongate for several months, when 

 further growth seemed to have ceased. To make certain of this, 

 the animals were kept for six months longer, but no further 

 change occurred. The new part was shorter than the part re- 

 moved, and appeared to be a single rod, tapering at the end, 

 without any external signs of toes. 



The normal fore- and hind-foot of the amphiumas that I used 

 had each three toes. Cope 2 gives a figure of the skeleton of 

 amphiuma showing a cartilaginous carpus of four or five pieces, 

 and three ossified metacarpals with ossified phalanges. In the 

 hind-foot there are three cartilaginous tarsalia, three ossified 

 metatarsals and three phalanges. 



After the legs had regenerated they were cut off, imbedded in 

 paraffine, and cut into sections. These showed in three of the 

 four cases that the two bones of the middle part of the limb have 



1 This is the case referred to in Towle's paper. BIOLOGICAL BULLETIN, II., 1901. 

 "Cope, " The Batrachia of North America," Bull. U. S. Nat. Mus. No. 34. 



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