394 SEA-SIDE STUDIES. 



to me that the granular structure might be peculiar 

 to the molluscs without shells ; but the bivalve Solen 

 and the Aplysia contradict such a suggestion. 



Again, in the brains of several young Tritons, or 

 Water-Newts, T could find no fibres ; none in that of 

 a young Frog ; few in that of an adult Toad ; none 

 in that of adult Pipefish [Syngnathus) ;■ none in 

 that of a Dogfish (Acanthias) of about a foot and a 

 half long. It would be perilous to assert that there 

 were absolutely no fibres in the brains of these animals, 

 but if there were any, they must have been exceedingly 

 rare, as I could not find one : and theory requires that 

 there should be one or more for every cell.* 



These facts are important as well as novel, and force 

 us to the conclusion that fibres are not necessary to 

 the conduction of nerve-force, although they may be 

 special organs of conduction, wherever they exist. The 

 point to which the reader's attention is required is that 

 nerve-force can be transmitted — that nerve-actions can 

 take place — in the absence of primitive fibres. This 

 mio'ht have been concluded from the structure of the 

 olfactory nerve alone, which, by a remarkable peculiar- 

 ity, shows a break in the continuity of its fibres, the 

 intervening space being occupied with granules only. 

 This is the case in all animals.t And I find a still 



* Plate VII., fig. 2, gives a hypothetical diagram of the relation of 

 fibres and cells in the spinal chord and brain, according to the latest 

 ideas. Whatever truth it may have in reference to the higher verte- 

 brates, it is certainly not applicable to those fish and reptiles I have 

 examined. 



t See the description of the olfactorius in Leydig, op. cit. 



