870 EXPERIMENT STATION RECORD. [Vol.40 



87-90; 8, pp. 189-1M; 5, pp. 227-240. fig. 1).— These six papers complete a 

 series of reviews, the earlier installments of which have been noted (E. S. R., 

 37, p. 866 ; 38, p. 776. ) 



VI. Cattle.- — In considering the inheritance of roan color, it is held that the 

 data furnishd by Wentworth (E. S. R., 30, p. 469) do not support the two- 

 factor hypothesis of that author, but rather the idea of a single factor without 

 dominance, the exceptions being accounted for on subsidiary hypotheses. The 

 results of Lloyd-Jones and Evvard (E. S. It., 36, p. 168), showing that white 

 is independent of red and black, are held to disprove the theory of " polygamous 

 factors" (multiple allelomorphs) advanced by Wilson (E. S. It., 38, p. 367) to 

 explain the roan condition. 



Contrary to Wilson ( E. S. R., 21, p. 470). the author holds that dun coloration 

 is due to a diluting factor added to black. The same factor added to red pro- 

 duces yellow or cream. Brindle coloration has not been satisfactorily analyzed. 

 Piebald conditions are independent of color, but no factorial Interpretation 

 the several patterns can be attempted with the scanty data available. 



VII. The horse. — Seven independent pairs of allelomorphs are recognized in 

 the horse. In general the work of different Investigators fits together har- 

 moniously. The anther Is unable to explain certain facts associated with horse 

 hybrids, especially the occurrence of chestnut mules when this color is never 

 seen in jacks and is recessive in horses. 



VIII. Svinc. — The fragmentary published data on color inheritance in swine 

 are collected. The white of Yorkshires is dominant to red and black, as was 

 shown by Smith ( E. S. K.. :<<», p. r.'.t), bnt is distinguished from the dominant 

 white of other mammals by the fact that this breed never transmits red in 

 crosses with Mack nor black in cross<«s with red. It is suggested that the 

 white in this case is an extreme dilution of red accompanied by the complete 

 lack of black exb nston. The absence of the dilution factor and the presence 

 of partial black extension results in the black with white (1. e., dilute red) 

 points of Berkshlres and Poland Chinas. By Change* in minor factors causing 

 intensity of red and restriction of black this pattern Is, it is suggested, trans- 

 formed into the solid red of Puroc Jerseys and Tamworths. The replacement 

 of partial black extension by total extension results in solid black coloration, 

 such as shown by the Essex; while the addition of factors for white belt results 

 in the Hampshire pattern. 



IN. The dog- live pairs of unit characters for coat color of dogs are held 

 to be more or less clearly indicated. 



X. The eat. — The subject which has attracted chief attention to color in- 

 heritance in cats is the fact that the tortoise-shell pattern rarely occurs In 

 males. The theories advanced to explain this require that an orange male 

 mated to a black female should give rise to black males and tortoise females 

 only. Mated to tortoise females he should produce black males and equal num- 

 bers of tortoise and orange females. In both crosses black females and tortoise 

 males have been recorded. The author points out that these discrepancies are 

 much more numerous among female offspring than among males, and that there- 

 fore the aberrant cases can scarcely he dismissed as faulty records. 



Seven pairs of allelomorphs seem to be fairly well indicated for the coat 

 color of cats. 



XI. Man.' — The available information concerning Inheritance of hair color, 

 eye color, premature grayness, albinism, and spoiling Is briefly summarized. 



The correlation between a component and between the sum of two or more 

 components, and the sum of the remaining components of a variable, .1. A 



