OF ANIMALCULES. 165 



figures 253 and 258^ place beyond a doubt their muscular 

 nature, and that they are the real agents in effecting the 

 motions of the animalcule. The four pair of muscles, 

 tn, Ji, o,p, take their origin from the opposite extremities of 

 the animalcule, radiating towards their insertion between 

 the fourth and fifth pair of nervous twigs ; m indicating 

 the dorsal pair, n and o the two lateral pairs, and p the 

 ventrical pair : these, with the muscles of the forked tail, 

 the seventeen belonging to the rotatory cilia before no- 

 ticed, form the greater part of the system, and all of them 

 appear to take their insertion from the inner membrane 

 of the envelope, and to be unconnected with the sur- 

 rounding integuments. 



The nervous ganglion is situated near the rotatory 

 muscles, towards the dorsal side of the manducatory organ 

 b, it consists of a cluster of glandular bodies, i, distinguish- 

 able by their greater opacity, and connected by a dorsal 

 vessel, h h, which traverses the entire length of the animal- 

 cule : from this longitudinal vessel proceed at nearly 

 equal distances nine pair of twigs, which appear at 

 first view to encircle the body, but when carefully 

 examined are found to terminate near the inferior side ; 

 they are more slender than the dorsal vessel, and like 

 it, of a whiter hue than the other integuments : these, 

 in the opinion of Dr. E., constitute the nervous 

 system, and strongly resemble that of the Ascidia, 

 so beautifully demonstrated by M. Savigney. That 

 these filaments and ganglia are not muscles, is evi- 

 dent from their form, their mode of insertion, and 



