OF NATURAL HISTORY. 305 



texture is very ftrong and compact : That the fmall animals 

 they contain fhould be able to pierce through fuch a rigid 

 fubftance is truly wonderful. 



In the general order of Nature among oviparous animals, 

 each egg includes one embryo only. A fingular fpecies of 

 eggs, however, difcovered by the celebrsitad Mr. Folks, late 

 Prefident of the Royal Society of London muft be excepted. 

 He found great numbers of them in the mud of fmall 

 rivulets. In fize they equalled the head of an ordinary pin. 

 They were of a brown colour^ and their furface was crufla- 

 ceous, through which, by employing the microfcope, feveral 

 living worms were diftincSlly perceptible. By dexterouily 

 breaking the fhell, he diflodged them ; and he found with 

 furprife, that eight or nine worms were contained in, and 

 proceeded from the fame egg. They were all well formed, 

 and moved about with great agility. Each of them was in- 

 clofed in an individual membranous covering, which was ex- 

 tremely thin and tranfparent. It were to be wifhed that the 

 transformations of thefe extraordinary animals had been 

 traced.- 



Some caterpillars, when about to transform, make a belt 

 pafs round their bodies. This belt is compofed of an afl'em- 

 blage of iilken threads fpun by themfelves, the ends of which 

 they pafte to the twigs of bufhes, or other places where they 

 choofe to attach their bodies. They likewife lix their hind 

 legs in a tuft of fiik. After transformation, the chryfalids 

 remain fixed in the fame manner as before their metamor- 

 phoiis. The belt is loofe, and allows the chryfalis to per- 

 form its flow and feeble movements. 



The whole moth-kind, as well as the fik-worm, immedi^ 

 ately before their transformation into the chryfalis ftate, cov- 

 er their bodies with a cod or clue of lilk, though the nature 

 of the fiik, and their mode of fpinning, are very different. 

 The cods of the filk-worm are compofed of pure filk. Their 



