74 Mr. Montagu's Description of Marine Animals 
decay while the other is alive; and the addition of any thing 
offensive produces contraction ; even fresh water. 
GORDIUS ANNULATUS. 
This beautiful worm is of a garnet red colour, with a pure 
white line along the back, and another on each side, extending 
the whole length; between these are two rows of minute white spots, 
commencing about an inch from the head, and extending quite 
to the posterior end, the extremity of which is rounded and white : 
the fore part of the head, except the upper lip, is also of that co- 
lour : at small irregular distances are white transverse lines or bands 
that encircle the body, some of which are broader than the rest. 
Length, six or seven inches : diameter at the anterior end, one 
line ; rather less at the posterior. 
This, like the preceding, is capable of great contraction, ex- 
pansion, and variation in shape ; spreading in some parts, while 
others rise into swellings : but its more usual form is a little 
flattened. 
Several of this species were taken in old shells, and amongst 
coralline, by dredging. In all probability it is not common ; other- 
wise an animal with such strong specific characters could not 
have been overlooked. 
Sipunculus Strombus. 
Body rather more taper than cylindric in its contracted state ; 
but, when extended, the anterior end, for nearly one half its length, 
is not above half the size of the posterior : it is quite round, and 
not the least depressed in any part ; the larger end seems less ca- 
pable of contraction than the anterior ; this latter being endowed 
with the singular property of retracting or withdrawing itself in- 
ternally, in the same manner as the common Limax withdraws the 
ocellated 
