Experiments in Transplatitmg Limbs 



253 



These experiments were controlled by transplanting normal hind- 

 limbs, to the same individuals that had received the nerveless buds, 

 the latter having been placed on the right side of the trunk, the 

 former on the left. 



At this period of development the rudimentsof both the fore and 

 hind limbs are little knobs or buds which project slightly from 

 the surface of the body, the fore limb being concealed, however, 

 by the operculum. Each of the limbs consists of a group of mesen- 

 chyme cells situated in the body wall between the somatopleuric 



Fig. 2 Sagittal section through the hind limb region of a larva of Rana palustris 1 1 mm. long 

 slightly younger than the embryo from which Fig. i was taken, p. ext-, hind limb; coel-, ccelom; n, 

 nerve reaching nearly to base of limb. X 133. 



mesoderm and the epidermis. The cells at this period are closely 

 crowded (Figs, i and 2), but as yet no differentiation of tissues is 

 noticeable. There is no visible difference between the limbs in 

 the normal and nerveless individuals except in respect to the nerve 

 fibers, which either run to or skirt past the base of the normal ones. 

 In this respect my own observations cannot be brought into accord 

 with those of Braus, who denies the presence of nerves in the nor- 

 mal limbs at this time. A careful study of numerous series of sec- 



