White-lipped Frog. White-jawed Frog. 



Plate LI V. i. After Broc- 

 chi (xf). 2. After Boulenger 

 (xf). 3, 4. After Schmidt 

 (Xf). 



Leptodactylus albilabris 

 (Giinther). 



Range: Vera Cruz to Nica- 

 ragua; also in Porto Rico and 

 Virgin Islands. Recently Dr. 

 E. ft. Taylor and J. S. Wright 

 took it near Rio Grande City, 

 Texas. This adds to the prob- 

 lem of its queer distribution. 

 In 1902 Dr. Stejneger knew 

 no parallel of this distribu- 

 tion and suggested its ac- 

 cidental introduction into the 

 islands by man, such as the 

 wrecking of a cargo of log- 

 wood or mahogany many 

 years ago. In 1914 Dr. Bar- 

 bour discards the accidental 

 agency of man and holds that 

 "it is more probable that the 

 Porto Rican and mainland 

 individuals have by some 

 fortuitous parallelism become 

 indistinguishable if they orig- 

 inally belonged to different 

 stocks, or if both were de- 

 rived from the same stock 

 then they have preserved 

 their identity in parts of their 

 range and varied with isola- 

 tion in other parts." Dr. 

 Noble in 191 8 points out 

 three characters of difference 

 between mainland and insu- 

 lar forms but frankly admits 

 no criterion is constant. K. P. 

 Schmidt in 1928 calls the 

 mainland and insular forms 

 very close but is not able to 



I 4 2 



