r-3 LONG SEA-WORMS. 



animals. If the head be cut off, a new head replaces it ; if the tail be severed, 

 a new tail is acquired." 



The mouth of the Planariae is a very remarkable structure. Near the 

 middle of the under surface there are two transverse slits, from the anterior 

 of which a funnel-shaped organ, like a cup, can be protruded. This acts as a 

 mouth ; it is soft, highly irritable, and when drawn within the body, is folded 

 up like the bud of a plant. This singular mouth opens immediately into the 

 stomach ; it can be protruded at pleasure, and applied to the surface of such 

 larvae or little worms as may come within reach, so as to suck from them the 

 juices that they contain, or if the prey be small, it is immediately swallowed. 



But the most wonderful creatures belonging to this group are 



The Long Sea- Worms (Nemertes)* occasionally to be met with by the 

 sea-side explorer, coiled up under loose stones. The length of this extraor- 

 dinary production of Nature is positively prodigious, and its whole history 

 has more the appearance of fable than of sober truth. 



"When I took it up at the sea-side," says the Rev. Mr. Davis ("Linn. Trans. :/ ), 

 "collecting such an immense creature into an oyster-shell, a very large one indeed, I 

 thought it would have been almost impossible to unravel it ; but it is astonishing to 

 think how easily it was disentangled, owing to the extraordinary smoothness of its 

 surface. It is impossible to make even a guess at the length of it when alive on account 

 of its always extending and contracting itself when touched, and that with such ease as 

 almost to exceed belief; but I may well say that it is capable of extending itself with- 

 out inconvenience to twenty-five or thirty times the length that it presents at another 

 period. It being impossible while the animal was alive to make any reasonable con- 

 jecture as to the length of it, I took it out of the bottle, and examined it when dead, 

 when I found it to be two-and-twenty feet long, exclusive of the proboscis. Now I 

 give it as my firm opinion, that I speak within bounds when I say the animal, when 

 alive, might have been extended to four times the length it presented when dead. It 

 is, therefore, by no means improbable that this most astonishing creature may have 

 been susceptible of being drawn out to the length of twelve fathoms, or, according to 

 the accounts of the fishermen, to thirty yards, or fifteen fathoms."' 



"The ignorant spectator, ''says Sir John Dalyell, "might almost suppose this animal 

 to be only designed to be an inconvenience to itself. Who can affirm that he has ever 

 seen the long sea- worm entire? that he had before him this giant of the race? or who 

 can presume that those, apparently of the largest size, shall grow no more ? 



" Unwieldy and unmanageable as this creature seems, it attacks and devours other 

 worms of all sorts. Portions of mussel are always acceptable, and are greedily swal- 

 lowed by its capacious mouth. If the valves of a mussel be sundered, the animal 

 fastens upon one of them, drags it away, and consumes the contents at leisure. When 

 he desires to shift his quarters, he stretches out his body like an enormous snake; the 

 eye sees no contraction of muscles, no apparent means of locomotion, but the micro- 

 scope teaches us that the Nemertes glides along by the help of the minute vibratory 

 cilia with which his whole body is covered ; he hesitates, he tries, and at last finds a 

 stone to his taste, whereupon he slowly unrolls his length to convey himself to his new 

 resting-place ; and while his entangled folds are unravelling themselves at one end, 

 they are forming a new Gordian knot at the other." 



s, nemertes, no mistake about it. 



