THE DEVELOPMENTAL STAGES OF AMPHIBIAN EMBRYOS 



starting with the (unpublished) Harrison series of stages for Amblystoma 

 punctatum, there have appeared more and more descriptions of the early develop- 

 mental stages of various forms. Through the generous cooperation of those who 

 have worked out the normal morphology of a number of different amphibian forms, 

 there follows .all the series and steiges that are now available. It is hoped 

 that this list will be extended, not only for the sake of research usefulness, 

 but in order to determine the extent of any deviations from a standard pattern 

 of development. The author desires to express, here again, his appreciation 

 for the cooperation of those who have made this collection possible. Reference 

 is made to Shumway, Polllster, and Moore, for Rana; to Weisz, Taylor and Kollros 

 for Xenopus; to Eakin for ^yla regilla; to Priscilla Anderson for Triturus 

 pyrrhogaster; to Twitty for Triturus torosus; and to Mrs. Naomi Leavltt who 

 painstakingly drew the Amblystoma series j.rom living and preserved material. 

 Identifying the various stages as in the (unpublished) Harrison series. 



On the following pages will be found the normal series for: 



Eana pi pi ens (Shumway) 



Rana plpiens (Mueller) 



Rana plpiens, photographs (Rugh) 



Rana plpiens metamorphosis (Taylor & Kollros) 



Rana plpiens, photographs of developmental abnormalities (Rugh) 



Rana sylvatica (Polllster & Moore) 



Xenopxifl laevia (Weisz) 



Hyla regilla (Eakln) 



Amblystoma punctatum (Leavltt) 



Triturus pyrrhogaster (Anderson) 



Triturus torosus (Twitty & Bodensteln) 



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