Microscopical Essays. 



ing ; but after the wheels are protruded, they are performed with 

 great regularity, fwiftnefs, and fteadinefs. 



Fig. 17, Plate XXVI. A, reprefents this little animal in what 

 Mr. Baker calls the maggot (late ; while in this form final 1 fpiculse 

 are feen to dart out near the anterior part ; the fnout is fometimes 

 more and fometimes lefs acute than in this delineation, (a) a 

 fmall horn near the thorax. 



Fig. 15 reprefents it s manner of moving from place to place^ 

 while in the maggot flate. 



Fig. 12 exhibits it, with the two femicircular parts, put out, 

 and in the pollure it places itfelf in when it is preparing to fwim 

 about, or going to put it's wheels in motion. 



Fig. 1 (hews the head at it's full extent, with a couple of fmall 

 bodies on the top of it, armed with fmall teeth like thofe of the 

 bal lance-wheel of a watch. 



At Fig. 18 the interior parts are more particularly exhibited, 

 (a) the circle from which many veffels originate ; (b) the thorax, or 

 breaft, joined to the head by the neck (c.) The part which is fup- 

 pofed to be the heart is plainly feen at (d.) The abdomen (f) is 

 feparated from the bread by a ring (e). (g) the tail 



Fig. 19 is the wheel animal, not full extended, but yet work- 

 ing it's wheels about. 



