260 NEBVES TO THE MUSCLES OF THE LEECH, 



legerement effilee ; elle ne presente ni plaques, ni 

 noyaux, ni substance finement granuleuse." 



The sti^ucture of these so-called JSTervenliuo'el in 

 insect- muscles was described and figui'ed by me in a 

 paper, accompanied by several drawings, read to the 

 Microscopical Society on June 1, 1864, and published 

 in the "Transactions" on October 1. Although 

 M. Rouget agrees with me as respects the nature of 

 the Nervenhiigel, we are at variance upon the farther 

 course and mode of termination of the nerve- fibre, 

 M. Rouget maintaining that it penetrates beneath 

 the sarcolemma and terminates there in a very fine 

 fibre, in contact with a veiy limited portion of the 

 contractile tissue, while I have been able to trace the 

 nerve for a long distance beyond the point at which 

 he makes it end, and have seen it dividing into very 

 fine fibres, which form an extended network upon the 

 sarcolemma, as represented in PI. XII, fig. 1, p. 263, to 

 which I beg to direct special attention. These nerves 

 are excessively fine, like the ultimate branches of the 

 tracheae which I have demonstrated in the same speci- 

 men. The preparation from which the drawing was 

 made was magnified nearly three thousand diameters. 

 M. Rouget's researches lead him to conclude that the 

 arrangement of the nerves in the muscles of Articulata 

 is totally distinct from that met with in Vertebrata. 

 " II result de ces faits qu'il n'y a pas d'identite entre 

 les divers modes de terminaison des fibres nerveuses 

 motrices chez les vertebres et les articules." On the 

 other hand, my observations lead me to the conclu- 

 sion that the arrangement is in its essential points 

 the same in all classes of animals. In no case are 

 there nerve-ends, but always plexuses or networks, 

 which are never in structural continuity with the 

 contractile tissue of the muscle. 



284. T>ferves to the muscles of the leech. — I have 

 particularly studied the arrangement and distribution 

 of the nerves in the leech. The same facts noticed 



