No. 3, April, 1921] GENETICS 253 



These two classes of characters differ in (a) their manner of origin, (b) their relation to 

 organic structure, and (c) their relation to phenomena such as recapitulation, adaptation, 

 distribution, and inheritance. It is held that characters which show recapitulation could 

 not have arisen through mutation, for that would modify every stage instead of adding 

 certain stages as it does. The unsuccessful attempts of many zoologists to explain away the 

 remarkable facts of recapitulation is noted. The apparent contradictions of von Baer's 

 law of animal development is held to be due partly to the occurrence of mutations in organ- 

 isms which already show recapitulation. — The author concludes that both types of characters 

 are necessary to account for the phenomena of evolution. The recognition of both types 

 involves the limitation of the cell theory and the admission of the neo-Lamarckian factor. — 

 J. H. Kempton. 



1757. G[ates], R. R. Orthogenetic evolution in pigeons. [Rev. of: Whitmax, Charles 

 Otis. Posthumous works. Edited by Oscar Riddle (vol. 3 edited by H. A. Carr). Car- 

 negie Inst. Washington Publ. 257. x + 194 P-, 88 pi, 36 fig.; 2U p., 39 pi, 11 fig.; xi + 161 p. 

 1919.] Nature 104: 566-568. 1920. 



1758. Good ale, H. D. Conceraing the summer plumage of the drake. (Abstract.) 

 Anat. Rec. 14: 92-93. 1918.— Some ducks, such as the Gray Call, Mallard, and Rouen, molt 

 early in the summer (June). The new plumage, called summer plumage, is entirely unlike 

 the old, since it strongly resembles that of the female. If the testes of the male are com- 

 pletely removed, the change in color no longer occurs, although the birds molt. Further 

 studies of the problem show that, potentially, the change in color of the intact male takes 

 place 2 or 3 months prior to the actual change, for the potential change, at will, may be ren- 

 dered actual by removing feathers and thus inducing a growth of new ones. The new feathers 

 that come in late in the winter are like the old, but those pulled a little later (March) are like 

 the summer plumage. This change coincides approximately with the beginning of manifes- 

 tations of sexual activity. — It has also been found that about the time the summer plumage 

 reaches its height, sexual activity diminishes or disappears. At this time the reproductive 

 system of the male contains few or no spermatozoa. The summer plumage no sooner reaches 

 its height than the change back to the breeding plumage begins. — 'It is apparent, therefore, 

 that the summer plumage develops coincidently with the period of greatest activity of the 

 testes, while the breeding plumage, so-called, develops during the quiescent period. — The 

 histological changes in the testes are being examined. — H. D. Goodale. 



1759. GowEN, John W. Conformation and its relation to milk-producing capacity in Jer- 

 sey cattle. Jour. Dairy Sci. 3: 1-32. 1 fig. Jan., 1920. — A biometric analysis of the rela- 

 tion between conformation and milk production in 1074 Jersey cows entered in the Registry 

 of Merit. The data on conformation are the detailed and total scores of about 140 judges, 

 collected by the Secretary of the Jersey Cattle Club. The average total score of these cows 

 was 89.8 where 100 represents the ideal type. Among the elements of conformation, those 

 pertaining to the mammary system showed most room for improvement. This same group 

 of characteristics was also the most variable. The correlation between total score and milk 

 yield for a year was + 0.194 =*= 0.016. Aside from total score the best indications of high yield 

 were found to be large, tortuous, and elastic milk veins (+0.191) ; udder large and not fleshy 

 (+0.191); rear udder well rounded out and well out and up behind (+0.171); body, wedge 

 shape, with deep large paunch, legs proportionate to size and fine quality (+0.166); and 

 general appearance (+0.115). Ten other elements in the score dealing with conformation of 

 thighs, rump, fore udder, teats, head, tail, general shape of udder, size, hip bones and neck 

 showed correlations with milk yield ranging from +0.089 to +0.050 which were probably 

 significant. There were positive but insignificant correlations in the case of eyes, horns and 

 muzzle and lung capacity as indicated by depth and breadth through body just back of fore 

 legs. The only negative correlation was in the case of straight back ( — 0.070 ='=0.017). It is 

 pointed out that other data show correlations between a seven day test and year milk yield 

 2| times as great as that between total score and year milk yield, proving that even a short test 

 of actual production is much superior to any judgment based on conformation. — Sewall Wright. 



