684 



DR. WALTER KIDD ON' THE 



[June 19, 



line nearly parallel with the mesial plane. This is universal in 

 Horses, and much more general than either A or B, being found 

 in most Ungulates and Carnivores. 



Fig. 3. 



CEPHALO- 

 HUMERAL, 



UPPER PART 

 ofPECT MAJ. 



LOWER PART 



of PECT. MAJ. 



EXTENSOR 

 CARPI-RADIAUS 



Front view of pectoral region of Horse, the left side showing muscles with 

 opposing actions, the right showing pectoral whorl with feathering. 



Two further points may be referred to. Eirst, neither A nor B 

 has been found in any but the Ungulate Order ; second, in 9 of 

 the 25 Ungulates noted, A and B co-existed. 



The suggested interpretation of these facts is that they are due 

 to the effect on the plastic hair-streams of the markedly divergent 

 traction of the underlying muscles. These are seen to have a 

 striking opportunity of influencing the structures lying over 

 them, in each of the three regions alluded to, by a reference to 

 the diagrams. 



