PLATE 2 
EXPLANATION OF FIGURES 
23 Medulla of the shield hair in the shaft below the isthmus. M, medullary 
cell; J, interstitial or intermedullary space. X 4000. 
24 Medulla of the shield hair midway between the isthmus and the tip of the 
shield. M, medullary cell. > 200. 
25 Shield hair of the tail, near the base. 535. 
26 Shield hair of the tail, midway from base to tip. M, medulla. X 45. 
27 Shield hair of the feet, midway from base to tip. M, medulla. x 45. 
28 Section through the shield hair of the tail, midway from base to tip. 
M, medulla; CU, cuticle; CO, cortex. X 73, 
29 Section through shield hair of the feet, midway from base to tip. M, 
medulla; CU, cuticle; CO, cortex. X 73. 
30 Showing the relations of the shield and fur hair on the dorsum of Ornitho- 
rhynchus. A, shield hair; B, fur hair; C, skin. X }. 
31 Showing the relations of the modified shield and fur hair on the chin area 
of Ornithorhynchus. A, modified shield hair; B, fur hair; C, skin. X }. 
32 Guide figure. 
33 Modified shield hair of chin, at A, figure 32. 200. 
34 Modified shield hair of chin, at B, figure 32. M, medulla. X 210. 
35 Modified shield hair of chin, below C, figure 32. X 200. 
36 Guide figure. 
37 Fur hair, A—-B, figure 36. X 450. 
38 Fur hair, C—D, figure 36. > 600. 
39 Single, isolated cuticular scale from the shaft of the fur hair, near base. 
x 1250: 
40 Fur hair at the base. M, medulla; CU, cuticle; CO, cortex. X 650. 
41 ‘Transverse section through the shaft of the furhair, midway between the 
base and tip. M, medulla; CU, cuticle; CO, cortex. > 700. 
42 Shaft of the fur hair, midway between the base and tip. M, medulla; CU, 
cuticle; CO, cortex. > 750. 
490 
