45 



nate the several nuclei of the general cutaneous system, I 

 therefore propose that the whole be called the general cutane- 

 ous nucleus. 



The general cutaneous nucleus is the continuation into 

 the oblongata of the dorsal cornu of the spinal cord, and it 

 carries its associated tracts with it. Its position will be 

 seen frorr Fig.2,g.c.n. In structure, it is indeed complex, 

 embracing as it does, three groups of neurones, large numbers 

 of nerve-fibres intercrossing in several directions, the spinal 

 V tract, and many supporting elements. The intrinsic neurones 

 will be considered first. 



a. The Molecular Layer. — The molecular layer appears in 

 a transverse section as a dorsal cap to the other constituents 

 of the nucleus (Fig. ?,m.l. ). It is seen to be continuous with 

 the cerebellar crest of the tuberculum acusticum. 



The neurones of the molecular layer are of two varieties, 

 the molecular neurones and the neurones of Purkirje. Both of 

 these varieties are identical with those described in Subsec- 

 tion 7 for the tuberculum acusticum; their morphology will 

 therefore not be given here. 



As to distribution, the minute molecular neurones are 

 found scattered through the whole thickness of the molecular 

 layer. The Purkinje neurones, on the contrary, lie only in 

 the deeper part of the layer, sending their great dendrites 

 into the upper levels. The possible phylogenetic significance 

 of the presence of the molecular layer in this part of the 



