DEPARTMENT OF EXPERIMENTAL EVOLUTION. 125 



than the form not hving in caves. This difference is small but fairly 

 constant. In general, so far as the evidence has been obtained, cave 

 animals are less reactive to photic stimulation and more reactive to 

 tactile stimulation than their near relatives living in other situations. 

 This was notably true of the common Asellus and its eyeless and pig- 

 mentless cave relative, CoBcidotea, with which Dr. Banta experimented 

 several years ago. The slightly modified cave form and the outside 

 form of Eucrangonyx gracilis showed the same differences, but in a 

 much smaller degree. 



As a by-product of these studies a paper has been prepared by Dr. 

 Banta and Dr. Gortner on an albino Spelerpes which was found while 

 collecting and saved for purposes of breeding, but which died before 

 reaching sexual maturity. It was an orange-yellow colored indi- 

 vidual possessing the normal amount of yellow pigment, but without 

 any black pigment in skin, eyes, or connective tissue. Aside from 

 the albinic axolotl, it is believed to be the only recorded case of an 

 albino urolele living in the open. Numerous albinic subterranean 

 uroleles are, however, known. 



HEREDITY. 

 Heredity of So7ne Emotional Traits, C. B. Davenport. 



A large amount of time during the past two years has been spent in 

 an analysis of family histories obtained by trained investigators. These 

 histories comprised families with some greater or less criminalistic 

 tendencies. As stated in my last report, the traits of more or less 

 periodic outbursts of hysterical temper and uncontrollable eroticism are 

 inherited as positive or dominant traits. Also, it now appears that a 

 family tendency to periodic depression accompanied by a suicidal 

 tendency is inherited as a negative or recessive character. Especially 

 striking has been the result of study of cases of dipsomania and allied 

 forms of alcoholism on the one hand and of nomadism or wanderlust 

 on the other, w^hich quite certainly prove an hereditary factor which 

 is inherited as a sex-linked one. Data are also presented demonstrating 

 the inheritable basis of inhibition or '' moral control." The whole work, 

 which is now ready for the press, is entitled "The Feebly Inhibited," 

 and gives a first clear insight into the hereditary basis of conduct. 



Heredity of Certain Mutations, C. B. Davenport. 



Further study of the "bare-neck" poultry supports the view, ex- 

 pressed in my last report, of the dominant nature of the factor that 

 prevents feathers from growing on the neck of these fowl. A brief note 

 on this subject, with photograph, appeared in the Journal of Heredity 

 for August. The case is important, since it is another clear example 

 of a morphological defect that is inherited as a dominant. 



