TO SURVEYS OF NATURE. ^ 56; 



toward the edge: the mouth and anus are both on the fame face, and 

 near together. On the upper face the figure of a five-petaled flower : 

 around it fix oval openings, having no apparent connmunication with the 

 'internal parts j^ points only within thefe openings. Native of the Weft 

 Indies. ' 



No. 6. Is white and flat, like the foregoing; differs by a kind of in- 

 cifions which almoft rcfemble the appearance of a fringe j in other, rc- 

 fpeds is finniiar. 



The Head and Eyes of a Drone Fly, fna^ified. 



This infed is remarkable for a large head and clufters of eyes : the 

 greateft part of the head confids of two feral-circular protuberances or 

 eyes. A, B B, C C, D D; whofe furfaces are repletl with minute he- 

 mifpheres difpofed triagonally, forming exact and cqui-diftant rows, with 

 little channels between them. Thofe in the upper divifions A, B, C, 

 much larger than thofe in the lower divilions C, D. Every one of thefe 

 ieems very nearly an exa^ hemifphere, refle6ling the images of fur- 

 rounding objects J infom.uch that hoofes, trees, &c. within a certain dif- 

 tance, appeared depi<5led on it, in the fame manner as the windows are 

 on the figure above. 



There were 14,000 pearls or hemifpheres in thefe clufters j 3000 of the 

 larger kind, 4000 of the fmaller kind, in each protuberance. Each pearl 

 is an eye, having the neceflary humours, &:c. yet probably the creature 

 has vifion only of fuch obje<^ls whofe rays of light fall nearly coincident 

 with the axis of the hemifphere j and of thefe fome may engage its at- 

 tention more than others. 



In the UbelUy or Dragon Ffyy Mr. Leuenhoek reckoned 12,544 pearls 

 in each eye, placed hexangularly ; he alfo numbered 6236 pearls in a Silk- 

 worm's two eyes when in a fly ftatc ; 318 1 in each eye of a BeetUi and 

 8000 in the two eyes of a common Fly, 



In flies and aerial animals the pearls are placed in triangular rows ; in 

 Crabiy Lobfters^ Shrimps, and other cruft:accous water animals (whofe 

 eyes are Icfs pearled) they are ranged in a quadrangular order: the lofs 

 in number being compenfated by a fmall power of moving their eyes 

 when infpefting objeds. - 



F F. The horns. 



G G. The fmeliera or feelers. 



H H I. The probofcis. 



K. Hairs and briftlcs, 



3 0^*- The 



