THE FUN OF SEEING THINGS 



49 



Animals with Extra Tails. 



The accompanying illustration of a 

 double-tailed earth-worm was sent to 

 us by Mr. H. E. Zimmerman, Mount 

 Morris, Illinois. The picture was for- 

 warded to Professor T. H. Morgan, of 

 the Department of Zoology of Colum- 

 bia University, New York. He replies 

 as follows : 



"Worms like the one in the picture 



This photograph was sent to Profes- 

 sor E. A. Andrews. He states as fol- 

 lows : 



The double earthworm figured is a 

 most interesting case and unusual in 

 that it is divided so far forward toward 

 the head, while all other double-tailed 

 worms known to me have the division 

 near to the hind end and' far from the 

 head end. Of the two tail ends shown. 



HAVE YOU EVER SEEN AN EARTHWORM LIKE THIS? 



which you sent me are occasionally 

 found and have been recorded from 

 time to time. They are due in practi- 

 cally all cases to an injury to the worm. 

 In some instances, the two new tails 

 have grown out from the broken end 

 of the worm. In other cases, the in- 

 jury on one side, involving the nervous 

 system, gives rise to a new tail ; or, to 

 be more accurate, continuation of the 

 body on one side. Professor E. A. An- 

 drews has described a number of worms 

 of this kind that he has obtained. 



"I think no one has yet been able to 

 produce these double-tailed worms by 

 artificially injuring the side, yet the 

 same thing has been done in salaman- 

 ders, where double limbs have been 

 produced by making wounds of certain 

 kinds on the stump of the old limb. 

 Double-tailed lizards are well known 

 and they, too, arise through injury to 

 the old 'tail." 



one is evidently much smaller than the 

 other and this is in harmony with the 

 findings in most all such cases of dou- 

 ble tail, so that the assumption that 

 one tail part arose as a sort of side bud 

 from the main trunk is a natural one. 

 It is unfortunate that a sharper photo- 

 graph was not obtained and that a com- 

 plete account of the anatomy is not 

 available, as from it one might hope 

 for more basis for inference as to how 

 the monstrosity came about. 



"The great interest that attaches to 

 all such cases of double ends, whether 

 of worms of of double-headed calves, 

 snakes, turtles and the like, seems to be 

 in the hope they hold forth that from 

 complete knowledge of the 'mistake,' 

 or abnormal, we may get a clearer view 

 of the causes of the average or normal. 



"When some one shall discover a 

 method of inducing such double ends 

 in earthworms, we may the better un- 



