122 NERVE COMPONENTS OF BONY FISHES. 



twig goes dorsad through the muscle to the skin under 

 which it continues caudad, at the same time turning 

 toward the median line. On account of imperfections in 

 the sections it could not be traced to its termination. It 

 seems strictly analogous with the other twigs which join 

 the r. lateralis accessorius, and I have no doubt that this 

 is its destination. 



It is probable that there are other cutaneous sense 

 organs in this region supplied from these anastomosing 

 twigs, which I have overlooked. Indeed in the younger 

 specimens examined these have been found, though their 

 nerve supply has not been traced. 



^. — TJie TJiird to Fifth Lateral Raimili. 



The ramus lateralis was not traced back beyond the 

 fifth ramulus. The last three ramuli observed are very 

 minute, containing only a very few fibres of medium size. 

 They run through the intermuscular septum, then dorsally 

 under the skin to the organ. The first free organ of the 

 trunk line is like the canal organs, large and flat topped. 

 The organs diminish in size caudad and assume more 

 nearly the characters of the smaller terminal buds, the 

 free sensory surface being protected by the upward 

 growth of the edges so as to give the whole organ a globose 

 form with a narrow and shallow pore at the apex. The 

 size of the fibres of the r. lateralis also diminishes as we 

 pass caudad. Near the ganglion both proximally and 

 distally of it, very large fibres predominate, some being 

 as large as 1 2 micra in diameter, and the average is about 

 4. The very large fibres soon disappear and as far back 

 as the level of the fifth spinal nerve the average size has 

 diminished to six micra or less. The size of the fibres 

 both here and in the case of the lateralis branches of the 



