Microscopical Essays. 



339 



Of thefe two mufcles, D is the only one that is altogether feen ; 

 it is very large, and diminifhes gradually in breadth, from ring 

 to ring, to the laft, branching off in fonie places. 



E is one of the ftrait mufcles of the back, and is inferted at the 

 divifions of it's own ring, under the dividing mufcles 9. 



Anterior Part of the twelfth Ring. 



There are three dorfal mufcles, D, E, F, to be confidered in 

 this part. 



The mufcle D is fimilar to D of the preceding ring, only that 

 it terminates at the fubdivifion of it's ring, and is confequently 

 only half as long. 



E is of the fame length, and differs from the mufcle E of the 

 preceding ring only in it's direction. 



The mufcle F is parallel to E, and Ihorter ; it's anterior end 

 does not reach the twelfth divifion. 



Posterior Part. 



There is only one dorfal mufcle here, which is failened by 

 fome fhort mufcles to the fubdivifions of the laft ring, traverfing 

 the mufcles a, and being fixed there, as if defigned to flrengthen 

 them, and to vary their direction. 



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