SPIRAL ARRANGEMENTS IN ANIMALS 



PLATE XIX 



35 



j^urri:Awo/m/^c 



YlG. 1. 



Fig. 3. 



Fir.. 2. 



Fig. 4. 



PLATE XX (continued) 



A. Vertebral column ; b, sterniun ; e, rib.9 ; d, scapula ; e, humerus ; /, radius ami ulna ; cj, bones of foot ; h, pelvis ; 

 i femur- j tibia and fibula; k, bones of foot. The bones of the limbs are not only twisted upon themselves but, in the 

 case of the radius and ulna, and the tibia and fibula, they twist round each other. The spirality resembles that seen in the bones of 

 the extremities of man (Plate xxi., Fig. 1) ; the wing of the bird (Fig. 185) ; the cast of the left ventricle of the heart (Plate xvii., 

 Fig. 3) ; and certain trees (Plate xi., Figs. 2 and 3 ; Plate xlii., Fig. 1) ; fruit (Fig. 16), and horns (Plate xv.. Fig. 2, D, E). 



Drawn by C. Berjeau from photograph specially taken for the Author. 



Fig 4 —Transverse section of turbinated or scroll bones of human skull (after Hirschfeld and Leveille). The middle (a, h) and 

 inferior'(c^ d) turbinated bones are distinctly spiral in their nature ; the right ones (a, <■) forming right-handed and the left ones left- 

 handed spirals. 



