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 in soft 

 mud, and one unceasing object of its life is the capture of prey. 

 Por 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 rim 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 sink 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 points 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 ApHRODiTACEiE. 

 Genus Spinther, Johnston, 



Char. Body oval, exannulate, scaleless^ acephalous ; antennse 



