Figure 20-4. Horizontal burrowing pattern of a single Nephtys 
incisa as indicated by the sequence of new afferent burrow 
openings appearing on surface of large sediment-filled box 
over a period of 2 weeks (18°C). 
NOTE: Afferent opening no. 11 indicates most recent burrow opening. 
Figure 20-5. Relationships of size of N. incisa to burrow length 
using a flexible cm rule. 
NOTE: Each vertical bar represents the range of 4-7 observations of a single 
worm of the indicated weight. N = 7 worms. 
310 
