1020] ANIMAL PRODUCTION. 669 



ran^'os are directly proportional to class moans. In this way the original un- 

 symmetrical frequency distribution becomes approximately symmetrical. Stand- 

 ard deviations of percentage frequencies " are used directly as coeflicients of 

 variation." 



The data cited are counts of the number of facets in the eyes of the bar-eyed 

 mutant of Drosophila melanogaster. 



The inlieritance of congenital cataract in cattle, J. A. Detlefsen and 

 W. W. Yapp (Amcr. Nat., 54 (1920), No. 632, pp. 277-2S0).— A registered Hol- 

 stein-Friesian bull had 03 normal offspring by a number of unrelated cows. 

 Thirty-two of the daughters were mated to a son and produced 63 calves, of 

 which S showed well-dclined congenital cataracts of the stellate type. It is 

 concluded that congenital cataract in cattle is a simple Mendelian recessive. 



Hereditary cataract in calves, C. P. Small (Amer. Jour. Ophthalmology, 

 S. ser., 2 (1919), No. 9, pp. 681, 682). — The author reports clinical observations 

 made at the Illinois Experiment Station on four of the blind calves noted 

 above, and on one calf got by the original sire out of one of his daughters. 

 The latter calf, which was 4 months old, had a soft cataract, while the others, 

 ranging in age from 6 to 23 months, had mature cataracts In both eyes. 



" Small chalky dots of further degeneration in the lens substance were seen 

 in most of the cases. ... In several of the eyes the lenses, apparently unde- 

 veloped In size, were seen throughout their entire circumferences, giving the 

 appearance of a glass marble suspended in the clear vitreous. The other ocular 

 conditions were practically identical in all the animals. Intraocular tension, 

 so far as could be judged, was normal. There was no ciliary nor conjunctival 

 congestion. Light perception and a good degree of light projection was found 

 in all cases. The pupils responded readily to light." Full mydriasis was 

 obtained in one hour with atropin and homatropin. 



The inheritance of coat color in Great Danes, C. C Little and E. E. Jones 

 (Jow. Ilercdity, 10 (1919), No. 7, pp. 309-320, fig. J).— The authors summarize 

 breeding records of Great Danes in the American Kennel Club studbooks. 



Solid black, brindlo, and fawn are interpreted, respectively, as complete 

 extension, partial extension, and restriction of black, and form a set of three 

 allelomorphs. These colors are also dominant to the corresponding dilute con- 

 ditions, the genes for intensity and dilution being allelomorphic. Harlequin 

 spotting (dominant) and solid color also form a pair of allelomorphs. The 

 appearance of small white spots on the chest and feet of the progeny of solid- 

 colored animals is thought to be due to a recessive gene for piebald spotting. 



It is pointed out that dogs, despite their slow breeding and large size, repre- 

 sent the best material among mammals for a relatively complete genetical 

 analysis. There are more color varieties, structural differences, and size 

 differences than in any other domesticated mammal, crossbreds are fertile, 

 and artificial insemination has been practiced successfully. The work of 

 Malone (E. S. R., 43, p. 2G9) showed that the number of chromosome pairs was 

 not large and indicattHl the possibility of .sex-linked inheritance. 



A note on the origin of piebald spotting in dogs, C. C. Little (Jour. 

 Heredity, 11 (1920), No. 1, pp. 12-15, flg. 1). — ^Two cases are reported of the 

 occurrence of white spotted pups in litters produced by solid-colored dogs 

 belonging to typically solid-colored breeds, Scotti.sh Terrier in one case, Aire- 

 dale in the other. In each instance the parents were somewhat related, and 

 it Is .suggested that by mutation an ancestor common to both parents became 

 heterozygous in.stead of homozygous for solid color. The white marks were 

 very conspicuous and could not have arisen by selection. 



Is there linkage between the genes for yellow and for black in mice? 

 C. C. Little (Amer. Nat., 5Jf (1920), No. 632, pp. 267-270).— The author con- 



