62 Proceedings of the Biological Society of Washington. 



frog, and one of the embryos was not sufficiently developed for 

 the scutellation to be recorded, so that the number of specimens 

 on which this study is based is 32 young and the mother. The 

 total lengths of 22 killed on November 13 ranged between 167- 

 200 mm. 



Variable Characters. 



The 32 young and the mother varied in tlie following characters: 

 number of supralabials, infralabials, nasals, loreals, preoculars, plates in 

 the second row of temporals, dorsal scale rows, ventral plates, subcaudal 

 plates and unbroken color bands around the body. 



Invariable are: the number of postoculars (3), the single plate in the 

 first row of temporals, the divided anal, and the divided condition of the 

 subcaudal plates. 



Supralabials. — Nine or eight present. The change is caused by the 

 splitting of the third plate counting from the front in specimens with 

 eight. The mother had 9-8. 



The young: Formula. No. of spec. Percent. 

 9-8 3 9 



8-8 29 91 



Nine 12 8 4 5 Eye 6 7 8 9 



Eight 12 4 5 Eye 6 7 8 9 



Infralabials. — Twelve to nine present. The change is caused by the 

 splitting of the last or the fourth and after these two the penultimate 

 divides giving twelve. 



The mother had 12-11. 



The young : Formula. No. of spec. Per cent. 



11-11 1 3.1 



11-10 5 15.6 



10-10 16 50.0 



10-9 6 18.7 



9-9 4 12.5 



Nasals. — Where there were three present there was a small upper 

 posterior nasal. Mother, 2-2. 



The young: Formula. No. of spec. Per cent. 



2-2 26 81.4 



2-3 3 9.3 



3-3 3 9.3 



