408 



BENNET M. ALLEN. 



individuals but we must consider mass results. There is a marked 

 decrease in the size of the body. This is out of all proportion to 

 the reduction in body size during normal metamorphosis. There 

 is marked decrease in the length of the tail amounting to com- 

 plete disappearance in one specimen which was unfortunately 

 not preserved owing to the drying up of the shallow water in 

 which it was necessary to keep it. In ten of the fourteen cases 

 here recorded, both fore limbs had broken through the skin and 

 in three of them the left one alone had appeared. 



The difficulties of rearing these larvae to complete metamor- 

 phosis are considerable, but not insurmountable. The small 

 size of the larvae is no doubt one factor. The sudden marked 

 shrinkage of the body is a decidedly abnormal feature. These 

 results are quite comparable to those attained by Swingle in 

 normal and in thyroidless tadpoles. The removal of the pituitary 

 gland in Bufo causes it to assume a light buff color in place of the 

 familiar intense black. This color change was in no wise modified 

 by the subsequent iodine feeding. Fig. I shows in graphic fashion 

 the nature of these changes as regards the typical feature of hind 

 leg length. The abscissae represent the length of body while 



TABLE I. 



the ordinates represent the length of the hind legs. The location 

 of any point serves to indicate the length of body by its hori- 

 zontal location and the length of the hind legs by its height above 



