8 Dr. Johnston on British Annelides. 
blance to the barrel of a dressed quill. It is about three inches 
in length; and the superior portion is thinner than the lower, 
which is very tough and not easily cut with a knife. I made a 
vain attempt to form it into a pen. 
Let us see if, in its curious structure, we can find a key to the 
habits of the animal. We learn from Miiller that it lives im soft 
mud, and one unceasing object of its life is the capture of prey. 
For this end it must protrude the anterior portion of the body 
beyond its tube, and raise it above the surface of the mud, and 
in this position remain on watch. To enable the worm to do this 
with ease, is, I conjecture, the office of the forceps-like bristles of 
the feet : with their ends it may hook itself to the mm of the 
tube, and thus support itself extended without the waste of mus- 
cular power. A long watch is thus rendered less irksome, while 
at the same time its capacity to seize upon a passing prey is in- 
creased. 
The prey caught, analogy leads us to believe that the worm 
will instantly retreat and smk within its tube, where it can feed 
without disturbance or fear. But as the entry and passage are 
narrow and unyielding, it seems to follow that the prey should be 
held by the mouth alone when in the act of being dragged within 
the tube, and hence surely the reason that the mouth has been 
furnished with the hard tubercles to the lips; for, when con- 
tracted, they must give a firmer gripe and hold than could other- 
wise be taken. 
The use of the tube is to protect the body from the pressure 
of the soft mud in which it stands immersed. When the tube is 
overset or cast out by the waves or accident, the worm leaves it, 
and becomes, in its turn, exposed to enemies. To protect itself 
from these while a new tube is being secreted, nature has amply 
furnished the Onuphis with a series of bristling lances on each 
side. These arms are of exquisite make, very fine and very sharp ; 
and those of the upper bundle have their pomts bent and in- 
clined towards those of the lower bundle, which are likewise bent 
to meet them. Do examine a foot under the microscope, and I 
defy you not to admire them: and your wonder will increase 
when you consider that a complex mechanism is also provided by 
which these polished instruments can be drawn within their 
sheaths, and pushed forwards and beyond at will. I can easily 
suppose that the wounds they inflict upon the tiny assailants of 
the Onuphis are severe and painful ; but worms are too retentive 
of life to permit us to believe that the repulsed foe ever dies of 
them. 
Family APHRODITACES. 
Genus Spintuer, Johnston. 
Cuar. Body oval, exannulate, scaleless, acephalous ; antennze 
