SCIENCE 



[N. S. Vol. XLIII. No. 1114 



dent on its flat side than when they are inci- 

 dent on its edge. The maximum sound-wave 

 pressure found by Altberg, for very intense 

 stationary waves, was about .26 dyne. Since 

 the pressure of a gas is proportional to the 

 absolute temperature, dT/T = dP/P. From 

 this it may be calculated that the increase of 

 temperature indicated by a thin bolometer 

 strip on which the waves exert a pressure of 

 .26 dyne would be about .000075° at atmos- 

 pheric pressure and a temperature of 17° C. 

 or 290° absolute. 



E. P. Lewis 

 "University of California 



RUDIMENTARY MAMM.ffi IN SWINE A SEX- 

 LIMITED CHARACTER! 



The inheritance of the rudimentary mammas 

 found on the lower part of the scrotum of the 

 boar and on the inside of the thighs to the rear 

 of the inguinal pair in the sow, was reported 

 as typically sex-limited by the writer in 1912 

 and 1913. Later, in 1914, due to the failure 

 to discover a boar homozygous for the char- 

 acter, an attempt was made to classify the in- 

 heritance as sex-linked in nature. Certain 

 more recent discoveries, due largely to a few 

 selected matings, have cleared up the diffi- 

 culties which in 1914 were believed to exist, 

 and make the earlier interpretation more 

 probable. 



The case in point is as follows : A Duroc 

 Jersey boar possessing the rudimentaries was 

 mated to a grade black sow lacking them. A 

 litter of nine pigs was farrowed, four of the 

 boars having rudimentaries, and one lacking 

 them, while three of the sows lacked rudi- 

 mentaries and the fourth possessed them. 

 Coupled with the evidence on the inheritance 

 of this character published previously, this 

 breeding performance indicates that both the 

 Duroc Jersey boar and the grade black sow 

 were heterozygous for this character. 



One of the boars possessing rudimentaries 

 from this litter was mated to the four sows of 

 the litter with the following results : 



1 Paper No. 2 from the Laboratory of Animal 

 Technology, Kansas Agricultural Experiment Sta- 

 tion. 



This breeding performance very definitely 

 indicates that the boar was homozygous for 

 the rudimentary mammae. All of the boar pigs 

 that he sired possessed the character, even 

 though two of the sows were of a type not to 

 transmit it at all. If he were heterozygous 

 for the character, then at least part of the 

 seven male pigs from sows 28 and 29 should 

 have lacked the rudimentaries; the chances 

 of their all having them being one out of 128. 

 The discovery of a boar homozygous for the 

 rudimentaries removes the principal stumbling 

 block to the simple sex-limited theory. 



Davenport and Arkell have developed a 

 scheme which bridges the discrepancies be- 

 tween sex-limited and sex-linked inheritance, 

 even when apparently homozygous animals 

 exist. Since, however, the sex-limited explana- 

 tion advanced by Wood seems to cover all 

 the facts that are involved in this case, and 

 since it is much simpler, the writer prefers 

 thus to interpret these results. 



Edward IST. Wentworth 



literature cited 

 Arkell, T. E., and Davenport, C. B. Horns in 

 Sheep as a Typical Sex-limited Character. 

 Science, N. S., Vol. 35, pp. 375-377. 

 Wentworth, E. N. Another Sex-limited Character. 

 Science, N. 6., Vol. 35, p. 986. 

 Inheritance of Mammse in Duroc Jersey Swine. 



Amer. Nat., Vol. 47, pp. 257-278. 

 Inheritance of Rudimentary MammEB in Swine. 

 Proc. Iowa Acad. ScL, 1914, Vol. 21, pp. 265- 

 268. 

 Wood, T. B. Note on the Inheritance of Horns 

 and Face Color in Sheep. Jour. Agr. Sci., 

 Vol. 1, p. 364. 



THE NATIONAL ACADEMY OF 

 SCIENCES 



The sessions of the annual meeting of the Na- 

 tional Academy of Sciences were held in the 

 United States National Museum, Washington, 



