853 



brain weights of 7 adiiil cocks and 9 adult liens'). The averages 

 are 124.1 grams tor the bodj weight and J. 223 giains for the brain 

 weigiit of the cocks, and 123 grams for the body weight and 1.242 

 grains for the brain weight of the hens. From this we may conclude 

 to the e(|ualily of the two sexes in both respects. 



An important sexual ditfereiice in body weight exists on the other 

 hand for the Domestic Hen. In what quantitative relation between 

 the two sexes is here the weight of the brain to that of the body? 



Careful determinations of weight for an adult cock and an adult 

 hen made by Falck -) and for an adult cock by Wklcker ') gave 

 the following results. 



Tiie body weight (without "ballast") of Falck's cock, which was 

 extraordinarily large for its breed, was 1745,67 grams, the brain 

 weight 3.82 grains, the (net) l)ody weight of the hen was 985.15, 

 and the brain weight 3.36 grams. From this we find an exponent 

 of relation 0.2248. By comparison of the same hen with Welcker's 

 middle-sized cock, which had a "Reingewicht" (net weight) of 1445.7 

 grams and possessed 3.7 grams of brains, we obtain an exponent 

 of relation of 0.2513. 



Given the comparatively much greater differences of the brain 

 weights between the two sexes, these results in themselves have 

 already a greater importance than those which Lapicque obtained 

 for the Sparrow. I found between an almost full-grown (more than 

 six months old) cock of the Leghorn breed, and an entirely full- 

 grown (two years old) hen of the same, but not quite pure breed, 

 the exponent of relation 0.4490 for (net) body weights of 1803 and 

 1197 grams (with emptied crop and stomach) and brain weights 

 of 3.75 and 3.12 grams. Seeing however, that this cock was not 

 fully grown, and was therefore too light for its brain weight, the 

 intersexual exponent of relation for the Gallus kind appears to be 

 half so great as for Man also here *). 



This is in concordance with what we find for different species 

 of mammals. When in the series of Max Weber's dogs ") the 7 



^) A. Hrdlicka, Brain Weight in Vertebrates. Smithsonian Miscellaneous 

 Collections. Vol. 48. Publication N". 1574 Washington 1905, p. 106. 



2) G. Ph. Kalck, Beitrage zur Kenntniss der Biklungs- und Waclislhumsge- 

 schichte der Thierkörper. Schriften der Gesellschafl zur Beförderung der gesammten 

 Naturwissenscliaflen zu Marburg. Band 8. Mirburg 1857, p. 165-249, (p. 242). 



^) R. Welcker — A. Brandt, Gevviclitswerthe der Körperorgane bei dem Menschen 

 und den Thieren. Arcliiv für Antliropologie, Band 28. Braunschweig 1902, p. 53. 



*) See below, p. 864. 



^) Max Wf:BER, Vorstudien fiber das Hirngewicht der Saugethiere. Festschrift 

 für Carl Gegei^baur. Leipzig 1896, p. 111-112. 



