112 CARNEGIE INSTITUTION OF WASHINGTON. 



To the difficulties in obtaining measurements of behavior of the dogs was 

 finally added an epidemic of distemper. In the face of such difficulties it 

 has become clear that the problem of inheritance of the elements of behavior 

 in dogs is too large and too expensive for this Department to undertake with 

 its limited resources. There is required for the work the cooperation of a 

 group of investigators including at least an animal behaviorist and a physiolo- 

 gist in addition to a geneticist. 



Heredity of Learning Capacity in Mice. 



Miss E. Vicari was a guest of the Department during the summer and con- 

 tinued her investigation into the rate of learning in mice, using for this purpose, 

 in addition to the strains which she reported last year, the abnormal-eyed 

 descendants of X-rayed mice and a closely inbred strain of dilute brown mice. 



The Inheritance of Cross-Bill in Pigeons. 



This character has appeared at various times in the past in connection 

 with other breeding work. During the past two years several matings have 

 been made by Dr. Riddle in order to test the mode of its inheritance. This 

 has not been determined, but the fact of inheritance is clear. It has also 

 been learned that the character is more properly described as "deformity of 

 the beak region." This manifests itself in various ways — absence of little 

 or much of upper beak or of lower beak, upturned beak, one or both nares 

 unclosed, wide or unusual gape. 



The Inheritance of Blood-Sugar Values in Generic Crosses. 



Our ample collection of pedigreed birds, particularly of hybrids from crosses 

 involving different genera, has made it possible to obtain a partial test of the 

 behavior in hybridization of such a physiological or chemical character as the 

 concentration of the sugar of the blood. This work was done by Dr. Riddle 

 with the cooperation of Dr. H. E. Honeywell. 



When it was learned that the Japanese turtle-dove (Turtur orieyitalis) has 

 a relatively high concentration of blood sugar, while the ring-dove (Strepto- 

 pelia alba) has the lowest amount of blood sugar of any of those measured 

 by us, we naturally selected the Fi hybrids of these two species for this test. 

 A study of the F2 hybrids is highly desirable, but this has not yet been made. 

 The individuals used to determine the amount of blood sugar in the parent 

 species were not the parents of the particular hybrids whose blood was 

 examined. All of the hybrids in our collection having this type of origin 

 were included in the study. 



The result of this inquiry indicates that 68 of these hybrids have a blood- 

 sugar value almost exactly intermediate to that found for the two parent 

 species. In these Fi hybrids the data for blood sugar indicate as truly an 

 intermediate value as do the data for size. An additional group of Fi hybrids 

 has been examined. Other studies in progress should soon make it possible 

 to estimate the significance and value of the results already obtained. 



Coat Colors in Dogs. 



In connection with the observations on coat color of the dachshunds and 

 chow-chows at this Department, Miss Jane Hubbard, in collaboration with 



