1092 THE THEORY OF TRANSFORMATIONS [qh. 



In the Abyssinian Equus Grevyi, all the stripes are very numerous, 

 narrow and close-set. The body-stripes refuse, as it were, to be 

 encroached on or obliterated by those of the hindlegs ; which latter 

 are merely intercalated between them, chevron fashion, wedging 



Fig. 554. Zebra patterns. A, B, Equus Burchelli; C, E. zebra; D, E. Grevyi. 



in between the body-stripes as the foreleg-stripes are wont to do. 

 It follows that in the middle of the haunch, over the region of the 

 hip- joint, there is in this species a characteristic "focus," where the 

 leg-stripes fit in between the lumbar and the caudal sections of the 

 body-stripes. We may now add, as a fourth and last series, common 

 to all kinds, the few stripes which surround the lips on either side, 

 and wedge in between the stripes upon the face. 



Conclusion 



There is one last lesson which coordinate geometry helps us to 

 learn; it is simple and easy, but very impprtant indeed. In the 

 study of evolution, and in all attempts to trace the descent of the 

 animal kingdom, fourscore years' study of the Origin of Species 

 has had an unlooked-for and disappointing result. It was hoped 



