SHORTER ARTICLES AND DISCUSSION 



THE INFLUENCE OF CAVE CONDITIONS UPON 

 PIGMENT DEVELOPMENT IN LARViE OF 

 AMBLY STOMA TIGRINUM 



One of the possible methods of approach to the problem of 

 the origin of the modifications of cave animals is by experiments 

 in which outside forms are kept under conditions normally 

 encountered by animals living in caves. In following up this 

 method of approach, it seemed best to select forms as plastic as 

 possible (if perchance there are forms which are plastic with 

 reference to modifications by cave conditions). Typical cave 

 animals, i. e., species highly adapted for cave life, perhaps 

 without exception belong to families and genera having many 

 members showing an inclination toward cave habitation either 

 by actually frequenting or living in caves or by inhabiting 

 similar dark and retired situations elsewhere; so that it might 

 seem that these groups possess a certain plasticity toward modi- 

 fications by cave conditions. Especially might this plasticity 

 be expected in the particular species which already show a tend- 

 ency to live under conditions resembling those of eaves. 



Young animals may be expected to be more responsive to 

 changed environment than adults, and since many of the uro- 

 deles live in caves and similar situations, and their eggs and 

 young can be obtained in numbers and reared with comparative 

 ease, amphibian larva' were selected for some of the experiments. 



Newly laid eggs of Ainhh/slonia lifjrinum were collected (in 

 some cases were laid in jars in the laboratory where some of the 

 adults were confined) from March 30 to April 4, 1911. The 

 eggs, in small lots, were placed in a number of 6-inch battery 

 jars, and the jars divided into two lots, Series A and Series B. 

 Series A was placed in the artificial cave while Series B was 

 kept on a laboratory table adjacent to and directly in front of 

 a west window. Otherwise the two series were, as far as pos- 

 sible, subjected to like conditions. Unfortunately it was not 

 possible to keep Series B at as low or as uniform a temperature 

 as Series A. Development was somewhat slower on the average 

 with Series A than with Series B, and both of these developed 

 slightly less rapidly than a third series, Series C, observed in the 

 pool where the eggs were laid and the larvae allowed to develop 

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