THE BEHAVIOR OF THE EPIDERAHS OF AMPHIBIANS 

 WHEN CULTIVATED OUTSIDE THE BODY 



S. J. HOLMES 

 From the Department of Zoology, University of California 



SEVEN FIGURES (OXE PLATE) 



In a previous paper^ I have described the formation of strands 

 and sheets ectodermic epitheUum from pieces of amphibian 

 larvae which were cultivated outside the body in lymph or 

 plasma. It was shown that these extensions of epithelium were 

 due to an amoeboid activity on the part of the cells at the edge 

 of the extending mass of tissue. This year when opportunity 

 for working on amphibian embryos and larvae was again pre- 

 sented, further observations and experiments on the behavior 

 of the epithehal cells led to the discovery of several additional 

 facts, as well as to the confirmation of the conclusions already 

 drawn. WTiere not otherwise stated the observations here 

 described were made on the larvae of Diemyctylus torosus. The 

 behavior of the epidermis from tadpoles of Rana and Hyla 

 proved to be essentially the same as in the species pientioned. 

 Studies were also made on the epithelial outgrowths from tissues 

 of the adult frog. 



Pieces of embryos were cultivated as before in lymph or plasma 

 from the adult. It is very difficult to employ plasma on account 

 of the rapid coagulation of the blood. Lymph has the practical 

 drawback that in most amphibians a very small quantity is 

 available while in the frog it varies so greatly that no uniform 

 lesults could be obtained with it. Lymph tends to become too 

 watery for use a short time after the frog is dead, and only a 

 few drops of a usable quality can be obtained from any one 

 animal. Epithelial cells do not wander out to any considerable 



1 Holmes, S. J. Behavior of ectodermic epithelimn of tadpoles when culti- 

 vated in plasma. Univ. of Calif. Pubs, in ZooL, vol. 11, 155, 1913. 



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