Chap. VII. 



THE EFFECTS OF DISUSE. 



273 



three-quarters of an inch too long relatively to the length of the skull 

 in comparison with these same parts in G. bankiva. 



In the following Table II. in the two first columns we see in inches 

 and decimals the length of the sternum, and the extreme depth of its 

 crest to which the pectoral muscles are attached. In the third column we 

 have the calculated depth of the crest, relatively to the length of the 

 sternum, in comparison with these same parts in G. bankiva. 76 



Table II. 



Names of Breeds. 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



Gallus bankiva . . . . male 



Cochin male 



irking ma i e 



Spanish ma l e 



Pohsh male 



Came male 



M a% female 



Sul tan male 



Frizzled hen male 



Burmese Jumper . . . . female 



Hamburgh ma i e 



Hamburgh f ema le 



bllkfo wl female 



Length 



of 

 Sternum. 



Depth of 



Crest 



of 



Sternum. 



Inches. 



4-20 



5-83 



6-95 



6-10 



5-07 



5-55 



10 



47 



25 



06 



08 



55 



49 



Inches. 



40 



55 

 97 

 83 

 50 

 55 



Depth of Crest, 



relatively to the 



length of the 



Sternum, in 



comparison with 



G. bankiva. 



1-50 



36 



20 



0-85 



40 

 26 

 01 



100 

 78 

 84 

 90 

 87 

 81 

 87 

 90 

 84 

 81 

 81 

 81 

 66 



By looking to the third column we see that in every case the depth of 

 the crest relatively to the length of the sternum, in comparison with 

 tr. baninva, is diminished, generally between 10 and 20 per cent. But the 



ST ? f : UC ! 10n VarieS much > P^ ™ consequence of the frequently 

 aeioimed state of the sternum. In the Silk-fowl, which cannot fly, the crest 

 £ a* per cent less deep than what it ought to have been. This reduction of 

 ne crest m all the breeds probably accounts for the great variability, before 

 Mtr* ■* Z , curvature of the furcula, and in the shape of its sternal 

 cnZT f i l men believe tllat tlie abnormal form of the spine so 

 mmrf. ff rVed in wom enof the higher ranks results from the attached 

 thevm ^ 0t . bemg Ml ? zeroised. So it is with our domestic fowls, for 

 examined h PeCt ° ral mUSCleS but little > and ' out of twenty-five sternums 

 ratelv w 7^' G alone were Perfectly symmetrical, ten were mode- 

 y crooked, and twelve were deformed to an extreme degree. 



Finally, we may conclude with respect to the various breeds 



ie fowl, that the main bones of the wing have probably 



een shortened in a very slight degree; that they have cer- 



^^o^pTti! 8 CalCUlatGd ° n the 8ame principle as explained in the 



VOL. I. . 



