LIMITS OF HEREDITARY CONTROL 921 
| ae. 
Fig. 15a Right-hand ends of the 8th and 9th bands of a shell showing two slight 
‘abnormalities,’ for a description of which see text. X 2. 
Fig. 15b Under surface of the affected regions of the preceding. X 3. 
Fig. 16 Under surface of a portion of the anterior half of the pelvic shield. 
Note the hexagonal shape of a majority of the bony plates. These are all per- 
forated by one or two small holes through which blood vessels and nerves pass. 
Ke 
