39 



stretched and hollowed, forms a kind of boat on the 

 surface. Its sides rise above the water so that none 

 gets in. But on the least agitation of the water, the 

 insect immediately shuts up his boat, and retires into 

 the mud. When the motion is over, he again thrusts 

 his tail out of the water, and makes his boat afresh, 

 which remains entire till he is disturbed again. And 

 this he does not fail to make, though the mud is re- 

 moved, and he left with little water. It seems the 

 organs of respiration are placed in this part, as they 

 are in various sorts of aquatic animals. 



These worms are quicker in their reproduction thaa 

 earth worms. They more easily recover their heads, 

 as well as tails, and this power exerts itself throughout 

 the whole year. 



The case of the snail may seem still m,ore strange. 

 It can first, reproduce its horns. After they hav 

 been cut off, the trunk becomes like a small knob, 

 whence springs a black point, which is the eye. The 

 trunk then increases io length and size, till it equals 

 the former horn. 



If the head be cut off, a new one succeeds ; but 

 in a singular manner. If a worm's head be cut off, 

 the reproduction is an entire organic body, that is, a' 

 part in miniature exactly similar to that which was 

 cut off. But what appears on the trunk of a snail, 

 is not an entire organic body, containing in miniature 

 all the parts of the head which were cut off, but 

 these parts grow piece by piece at different intervals, 

 and require time to unite and consolidate into one 

 mass, resembling the original pattern. For instance. 

 Sometimes the reproduction is like a small round body, 

 containing the primary parts of the two lips, and of 

 the small horns, which are united to themouth, and 

 to the new formed teeth. This round body is placed 

 on the centre of the trunk. The large norns and 

 the fore-part of the snail, which in the -entire ani. 

 mal are contiguous to the head, are wanting. Ano- 

 ther trunk shews the larger horn on the right side. 



