&g6 Animalcules with Shells and Wheels • 
and makes ufe of it on other 'Occafions* 
which we fhall prefently take Notice of. 
Its Body- feems divided into three Parts, 
the Head, Thorax, and Abdomen; each 
whereof is capable of great Diftentioh .and 
Contraction; the Creature being able by 
Extending them all three to protrude its 
Head beyond the Shell, and on the contra¬ 
ry, by contracting them, to draw its whole 
Body a great Yfay within the fame. 
The Head when extended divides into 
two Branches, between which another Part 
(a Kind of Probofcis) is pufhed out, at 
whole End are two Fibrils, that appear 
when at Reft like one very broad Spike, but 
which it can move very brilkly to and from 
each other with a vibrating Motion , bring¬ 
ing thereby a Stream of Water to its Mouth, 
whofe Situation is juft betwixt them. And 
the better to effect this, feveral of the like 
Fibril lee are placed on each Side of the Head, 
which vibrate in the fame Manner, as do 
like wife fome very fmall ones at either Cor¬ 
ner. All this may be uoderftood by view- 
ing fig- 4 * , 
But fometime's it alters the form of the 
two Branches, rounding the Ends thereof, 
and changing the vibrating Motion of its 
Fibril lee. intp a Rotation, or at leaft wha| 
ieeras to be fo $ at which Time the HeacJ 
appears as at fig. 5, 
