270 Chapter 11
note are Paralimnoriaand Phycolimnoria. The adult animals are whitish grey
in appearance and are quite small, ranging in length from 2–4 mm (Figure 4).
The galleries and tunnels they excavate at or just below the wood surface
are 1–3 mm in diameter and the resulting network of tunnels has a lacework
appearance. Sloughing off of the surface remnants produces an eroded appear-
ance to badly damaged wood which is commonly most pronounced in the inter-
tidal zone.
Limnoriids are highly mobile. The animal has a head, a segmented thorax
and abdomen, with seven pairs of legs positioned ventrally under the thorax.
Pleopods positioned under the abdomen function as gills and are used in
swimming. The last two posterior segments of the animal – the fifth pleomer
Figure 3Burrows of pholads in wood
(Photo courtesy of Dr Simon Cragg)
Figure 4Light micrograph of Limnoria sp.
(Photo courtesy of Dr Simon Cragg)