No. 4, February, 1922] GENETICS 263 



forming a pointed arch in the regions where body and extremities meet; (2) longitudinal stripes 

 presumably a primitive pattern, as found in young swine and tapirs; and (3) "streaming" 

 type, found only in domestic animals (cattle and dogs principally), in which vertical striping 

 extends over back and rump, and circular striping fails to develop on the extremities. Each 

 of these types appears to be hereditary, although asymmetrical and fortuitous patterns may 

 arise, due to developmental dynamics. The author's researches in perissodactyls and their 

 hybrids lead him to believe that the striping pattern and its variations are correlated with 

 accompanying or resultant phenomena of growth processes. He observed that the 1st type 

 of striping is closely related to the folds in the skin of young mammals, especially of newly 

 born rabbits. He believes this folding due to specific pulling and pressure relations on the 

 skin. On the basis of data submitted by Schumacher on a foetal wild hare, the author estab- 

 lishes a relation between the median stripe of the foetal hare and the 2nd type of striping as 

 represented in the dorsal stripe of Equidae, and regards the flecking such as occurs in the 

 civet cat and Viverridae in general as a transitional phase between the 2 types. Schultz's 

 experimental induction of black melanin formation in albino rabbits by means of cold ap- 

 plied to the high folds of the skin, is noted, but the author thinks that the stripes in cases he 

 has studied follow the infolds of the skin. It is suggested that the patterns are due to "bi- 

 ological interference" at a critical developmental stage, and are related to the arrangement of 

 pigment-forming cells in rabbits of English pattern, whose spotting conforms in a broken way 

 to type 1. — Edward N. Wentworth. 



1722. KuiPER, K. Color inheritance in cattle. Jour. Heredity 12: 102-109. Fig. i~8. 

 1921. — The author reports a study of inheritance of color in Dutch Belted cattle. These 

 cattle are usually black and belted, but self-black, self-red, and red belted are occasionally 

 produced. Also, there are wide variations in the belting pattern. From matings of belted 

 bulls and belted cows 50 calves were produced, 7 of which were self-colored (6 blacks, 1 red) 

 and 43 belted. A belted bull was mated to more than 60 piebald heifers, 6 of them red and 

 white, but most of them black and white. Of 55 calves produced, 27 were belted, 24 or 25 self- 

 colored, and 3 or 4 pied. The self-colored were in general coal-black, but some showed a 

 small white spot on belly, forehead, or tail-end. In only 1 case was it doubtful whether the 

 animal was self-colored or pied. Crossing a piebald bull and belted cows gave IS belted, 

 2 self-colored, and 1 piebald. Differences between the 2 ratios can be explained on the basis 

 of different genetic constitution of parents in the 2 crosses. Irregularity of color patterns 

 in the cross-breds is discussed. Taking B = belt, b absence of belt; S = self-colored; and 

 s = piebald pattern, the ratios obtained could be accounted for by a repulsion between B 

 and S giving 1:7:7:1. If the belted bull were of the formula BbSs he would form gametes in 

 the following proportion: 1 BS : 7 Bs : 7 bS : 1 bs. Mating such a bull to pied cows {bbss) 

 the result would be 1 BbSs : 7 Bbss : 7 bbSs : 1 bbss, or 8 belted, 7 self-colored, and 1 pied, which 

 agrees closely with observed results. Other types of mating are discussed in the light of 

 this explanation. — E. Roberts. 



1723. Lakon, Georg. Die Weissrandpanaschierung von Acer negundo L. [White- 

 margin variegation of Acer negundo.] Zeitschr. Indukt. Abstamm.- u. Vererb. 26: 271-284. 

 14 fig. 1921. — The white-edged leaves of a tree of Acer negundo are shown to be due to a 

 periclinal chimera constitution of the chlorophyll-containing cells, a phenomenon similar 

 to that in Pelargonium. Some stems and branches show the variegation as sectorial chimeras. 

 The whole plant is considered a "highly complicated, mixed chimera," both periclinal and 

 sectorial in nature. Inheritance of this variegation is not given. — E. W. Lindstrom. 



1724. Laughlin, Harry H. Dice-casting and pedigree selection. Experiments which 

 picture mathematically close analogies between dice-casting and certain breeding phenomena. 

 Genetics 6: 384—398. 3 fig. 1921. — By suitable casting of dice, it is possible to picture mathe- 

 maticallj' various phenomena of inheritance, such as filial regression, the rating of pure lines, 

 the effect of selection within pure lines, and the effect of selection based on the somatic char- 

 acter. Six dice, lettered a to /, are used. The faces of die a are marked 1-6; of die b, 2-7; 

 of die c, 3-8; and so on to die/, which is lettered 6-11. Each die represents a definite geno- 



