3. 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Starting with the (unpublished) Harrison series of stages for Amblystoma punctatum, there 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 developmental 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 

 stages 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 appre- 

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

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

 Xenopus: to Eakin for Hyla regilla; to Priscilla Anderson for Triturus pyrrhogaster ; to 

 Twitty and Bodenstein for Triturus torosus; and to Mrs. Naomi Leavitt who painstakingly 

 drew the Amblystoma series from 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 stages as in the (unpublished) Harrison series.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: 



Rana pipiens (Shumway) 



Rana pipiens (Klueller) 



Rana pipiens, photographs (Rugh) 



Rana pipiens metamorphosis (Taylor & Kollros) 



Rana pipiens, photographs of developmental abnormalities (Rugh) 



Rana sylvatica (Pollister &c Moore) 



Xenopus laevis (Weisz) 



Hyla regilla (Eakin) 



Amblystoma punctatum (Leavitt) 



Triturus pyrrhogaster (Anderson) 



Triturus torosus (Twitty h Bodenstein) 



a. Rana Pipiens 



NORMAL STAGES IN THE DEVELOPMENT OP RANA PIPIENS 

 WALDO SHUyWAV 



Sdwc Numbia 



Im-tiauna lO'C 



# 



StAM NuMUR 



Am-Houu«i IffC 



1 15 



50 





o 





(See also Shumway 1942 - Anat. Rec. 83:309) 



