NOTES ON REGENERATION. 



l6/ 



might represent a leg ; but he withdraws this interpretation at 

 once as seen above. There is certainly no striking resemblance 

 between the new part figured by Loeb and the abdomen of Ain- 

 mothca. Finally, if the new part is a new thorax where are the legs ? 

 In the light of these considerations we must wait until some 

 one, favorably situated, has an opportunity to work over the 

 subject with ample materials. Meanwhile it seems to me that so 

 far as the evidence goes it is rather in favor of the view that the 

 regeneration described by Loeb is a new leg and not a part that 

 replaces the lost segments of the thorax and abdomen. 



THE LACK OF REGENERATION OF THE PIGMENT SPOT IN 



THE FlN OF FUNDULUS. 



If a gold fish having a black band at the end of its tail be 

 selected, and the end of the tail be cut off proximal to the band, 

 a new band like the one removed reappears in the regenerated 

 tail. The presence of black pigment at the cut surface from 

 which the new part regenerates is clearly not necessary for the 

 development of pigment in the new part. This result is all the 



FIG. 4. 



more curious since the occurrence of the pigment band is only an 

 individual peculiarity. It seemed desirable to try the same ex- 

 periment in a species in which a characteristic spot or a ring was 

 present. The dorsal fin of the male of Fundiilus majalis has a 

 black spot in its posterior part, Fig. 4. The spot is not present 

 in the female, and it appears, therefore, that this color marking 

 belongs to the category of secondary sexual characters. 



The posterior part of the fin was cut off by an oblique cut ; 

 the part removed containing all of the black spot. The lost part 

 was slowly replaced, and in the course of two months the fin was 

 completed, but the pigment spot did not come back, and there 



