Geophilomorph centipedes and the littoral habitat - Books and ...

22 A.D. Barber / Terrestrial Arthropod Reviews 4 (2011) 17–39
Figure 2. Hydroschendyla submarina (Grube, 1872) as found coiled up in a rock crevice at Wembury,
England.
When burrowing in an earthworm-like manner, the large number of short segments
each of which can shorten and thicken allows extension and contraction of trunk
regions. In addition the head is relatively small and often tapered with mouthparts
which sweep semi fl uid material from their partially externally digested prey into
the digestive system. Th e anterior third of the trunk (in front of the so called “transition”,
if present) may be very distinctively tapered and with the narrow oesophagus,
heart and nerve cord having been described as centrally positioned to minimise deformation
by changes in the dimensions of the segments. Manton describes the cuticle
as being thicker in this anterior region and forming an armour of sclerites including
intecalary tergites and sternites which allow for changes in shape whilst at the same
time individual sclerites have fl exibility at the margins and stiff ness in the centre so
that thrusts can be transmitted but the armour remains intact and the plates do not
crack. In addition the longitudinal muscles are relatively large. An anterior region of
the body of the head and anterior trunk with relatively stout legs, adapted for strong
slow movements, allows extension and contraction of the front of the body with headon
burrowing to make the burrow wide enough for the remainder of the body to
follow. ( Figure 3 )