158 NERVE TUFTS AND EMINENCES. 



go into the question in detail. It is sufficient to say that, according 

 to Kiihne, in many of the invertebrata and the amphibia the motor 

 nerve ends in a sort of tuft or eminence upon the sarcolemma at 

 one or more points, and that here the sheath of Schwann becomes 

 continuous with the sarcolemma, so that the axis cylinder thus 

 penetrates the sheath and comes into contact with the fibre 

 itself. Here it frequently spreads out into a branched end 

 plate, or "layer of protoplasmic muscle substance that may 

 stretch to a variable extent into the contractile part of the fibre" 

 (209). Rouget also describes in lizards a mass of nuclei and 

 granular substance, beneath the point of entrance of the nerve. 

 Kiihne states that the nerve eminences vary much in form and 

 size in the Reptilia. In the Lacerta agilis the plate he gives of 

 the " terminal nerve plate," or the " motor nerve plate," is copied 

 into many text-books, and the nerve is here seen terminating in 

 a large, non-granular, thin layer. The thickness of this is con- 

 siderable, and in the central part is nearly as great as the short 

 diameter of a nucleus of the basis substance (223). Kiihne con- 

 cludes, that although there is so much variety in the termina- 

 tion of motor nerves in muscles, that no single scheme can 

 comprehend them all [this is denied by Beale, as said above], 

 yet, " The extremity of the axis cylinder always corresponds 

 to a remarkably broad expansion, which constantly forms a 

 flat branching mass" (227). Beale, as we have seen, denies that 

 the axis cylinder ever penetrates the sarcolemma, but admits 

 the existence of structures resembling the above outside the 

 sarcolemma ; he says, also, that although the latter is drawn into 

 a sort of eminence at the point where the nerve begins to ramify 

 over the fibre, that eminence is not a special organ. With respect 

 to the " end plates " and <( tufts," Beale has not found them in 

 the muscles of animals generally in fact they are rather excep- 

 tional though he has found them in the lizard and chame- 

 leon, and that they are not terminal organs, but display fibres 

 passing both to and from them. In fact these tufts are redup- 

 lications, and expansions, and coils of nerve-fibres interspersed 

 with large masses of bioplasm, which last are conspicuous in 

 Beale's plates, xii. and xiii. (" Biopl.," p. 263). Beale's conclu- 

 sion respecting the " nerve tufts " is as follows : 



