232 MODE OF TERMINATION OF MOTOR NERVES, BY W. KUHNE. 



this fibre system, in opposition to all analogy derived from the Verte- 

 brata, penetrates the granulated substratum, and comes into direct 

 contact with the contractile substance. Engelmann's observations 

 (67), at all events, expressly establish the latter point. 



To all appearance, the general results of inquiry upon the important 

 question of the mode of termination of the motor nerves seem to show 

 that the views of Remak, Beale, and Kolliker must generally be given 

 up, whilst Rouget admits that in the case of Crustacea, at least, the 

 axis cylinder does not terminate in a band-like and granular manner. 

 It appears, lastly, from the very recent brief essay of Krause (64), 

 that this author also has given up his two former views in respect to 

 the muscles of Amphibia, and has now actually seen the fibre system 

 of the intra-muscular axis cylinder, and also, by the application of the 

 colouring method with solutions of gold, the exceedingly beautiful 

 form of the nerve plate in the muscles of Lizards. The next step that 

 has now to be taken in advance, is to interpret the relations of the 

 lower surface of the plate to the granulated substratum. The author 

 is unable to express an opinion upon the statements of Trinchese (63), 

 which relate to the nerve eminence of the Torpedo. According to 

 this observer, the nerves of this fish possess duplicate sheaths at their 

 extremity, of which only the perineurium is continuous with the sar- 

 colemrna, whilst the nucleated sheath of Schwann accompanies the 

 axis cylinder where it penetrates into the nerve eminence, and every- 

 where loosely invests the flat plexus formed by the division of the axis 

 cylinder. Trinchese describes peculiar ganglionic enlargements on 

 the thus modified axis cylinder, and true terminal ganglion cells, with 

 nucleus and nucleoli, on the projecting extremities of the network ; 

 other nuclei distributed through the nerve eminence he refers to the 

 sheath of Schwann contained in the muscle. The drawings of Trin- 

 chese, although taken from preparations materially modified by diluted 

 hydrochloric acid, and undoubtedly deprived of their best qualities, 

 show what excellent materials were at his disposal, and render it ex- 

 tremely probable that these animals present the most magnificent 

 motor terminal plates in existence, though the delicacy and beauty of 

 their form are lost in all but physiologically fresh specimens. 



LITERATURE. 



1. DOYERE, Memoire sur les Tardigrades. Ann. des sciences nat., 

 2 de Serie. 1840. PL xvii., Fig. 14. 



