( n ) 



the microfcope, in order to view the means by which they can faften 

 thenifelves to the glafs and nin up it ; and I have, for fome years paft, 

 thought that I could difcover that thefe hairs, were each of them 

 provided with crooked parts like hooks, by the help of which they 

 can take the firmer hold on glafs, but which parts have never, to my 

 knowledge, been defcribed by any perfon, though the figures of thofe 

 hairs may be feen in many authors. 



In further profecution of this enquiry, and revolving the fubje6l 

 in my mind, a thought occurred to me refpe6ting thofe large crabs, 

 which are fometimes brought to this town for fale, and are, as I am 

 informed, caught among the rocks in Norway ; but not that I would 

 at all compare thefe crabs to flies, or that kind of animalcule, other- 

 wife than by analogy, for the feet of thofe crabs are covered with 

 many hairs. I therefore determined to infpedl them, and examine 

 the hairs, particularly thofe on the hind feet ; for thofe feet are not 

 furnifhed with claws, or other weapons, to grafp hold of any thing 

 like the fore feet, but only with one flraight claw, and with many 

 fliort hairs. 



Upon placing these hairs before the microfcope, I faw, not with- 

 out admiration, that many of them were provided with a double 

 row of parts like teeth, placed in very exad; order befide each other, in 

 like manner as if we were to imagine the back of a knife cut into 

 a double row of teeth or notches. I have caufed a drawing to be 

 made of one of thefe hairs, in order to fhew its wonderful formation, 

 which I am perfuaded is intended for this purpofe, that when the 

 crab is climbing up the rocks, he may be enabled by this afliflance 

 to fix his feet firmly on the rocks or flones. 



Fig. 6, MNOPQR, reprefents this hair, in which thofe tooth- 

 like parts are very plainly to be feen, but only one fide of the hair 

 is here vifible, and thefe teeth in the middle of the hair are longer, 

 as from Q to P, and from P to R they grow gradually fhorter. 



Fig. 7, ST, reprefents a part only of the hair, but in fuch a 

 pofition that the two rows of teeth in it are confpicuous. 



