122 



W. W. SWINGLE. 



TABLE III. 



APRIL 29. 



Length. 



no differences between the animals of the two groups were 

 observed. When examined under the microscope, both the 

 control and thymus-fed larvae had hind limb buds. The limbs 

 had not as yet differentiated into their two primary divisions, 

 nor had the toe points developed. The limb buds of both 

 groups of animals appeared to be of nearly the same size and in 

 the same stage of development. The thymus No. 2 group of 

 larvae had by this time outstripped the thymus No. I group in 

 growth. 



The table below shows that the control animals of the thymus 

 No. i group averaged, upon this date, somewhat greater length 

 than any of the thymus-fed larvae. The animals of the thymus 

 No. 2 group were somewhat larger than their controls. 



OBSERVATIONS OF MAY 8. 



The thymus-fed larvae upon this date were distinctly darker 

 in color than their controls; no other differences were observed 

 in the two groups of tadpoles. Both controls and thymus-fed 



1 l.b. = limb buds. 



