gcp Microscopical Essays, 



Thefe four lines, which we may conceive to divide the cater- 

 pillar longitudinally into four equal parts, are attended with this 

 remarkable circumftance, that each of them mark the place under 

 the fkin that is occupied by a confiderable vifcera ; the heart, or 

 rather the thread of hearts, lies under the fuperior line ; the 

 fpinal marrow immediately over the inferior line ; the two tra- 

 cheal arteries follow the courfe of the lateral lines. 



At equal diftances from the fuperior and two lateral lines, and 

 the inferior lines, we may fuppofe four intermediate lines. The 

 two between the fuperior and lateral lines are called intermediate 

 fuperior lines ; the two others which are oppofite to them, and 

 between the lateral and inferior lines, the intermediate inferior 

 lines. 



An Explanation of Figures i and 2, Plate XII; or an 

 Account of the Muscles of the Caterpillar when 



OPENED BY THE BeLLY. 



Of all the interior parts of the caterpillar, none prefent fo 

 beautiful a view, or a more wonderful and fymmetrical arrange- 

 ment, than that of the mufcles ; the more fo, if they are taken 

 away by equal ftrata on both fides, fo as to expofe at the fame 

 time the flmilar mufcles on the oppofite fide, and by this means 

 exhibit to the aftonifhed eye their exa6l form and correfpond- 

 ence. 



Fig. 1 and 2 is a reprefentation of the mufcles of two difFerent 

 caterpillars, Opened at the belly, and fuppofed to be joined to- 

 gether at the fuperior lines 5 for as the mufcles on the oppofite 

 6 fids 



