$ii Journal of Comparative Neurology. 



pHcity of the lateral line system in Menidia as compared with 

 many other fishes, especially the lower fishes, to be regarded 

 as primitive simplicity or as the result of degeneration ? Cole 

 would say the former, for he argues that the naked condition 

 of the sense organs is always the primitive, and that in the de- 

 cline of the system these organs are lost before the canals. But 

 how about the Amphibia in which the system is fluctuating on 

 the verge of the extinction and yet no canals are present, only 

 naked organs ? On the whole, I incline to regard the condition 

 in Menidia as reduced, rather than primitive." But can Prof. 

 Herrick produce any evidence to show that the lateral line sys- 

 tem ever was below the surface in Amphibia ? It seems to me 

 that the lateral line organs are characteristically superficial in 

 recent Amphibia, and the fossil forms apparently show the same 

 thing. Moreover, when I state that the primitive lateral line 

 system must have been a superficial one, I do not imply the 

 converse, that any fish having superficial lateral line organs has 

 a primitive lateral line system. Further, it is inconceivable 

 that there can be any degradation of a tubular lateral line sys- 

 tem which is not set in motion by the degeneration of the sense 

 organs themselves. There are several cases in the literature 

 where it would seem that the sense organs have almost disap- 

 peared and left the canals behind. The latter then seem to 

 have varied considerably. On the other hand, Menidia may be 

 a teleostean, and therefore a specialized fish, and still have a 

 developing lateral line system, although this would not be ex- 

 pected ; or its sense organs may have been reduced both in 

 number and complexity and involved the consequent movement 

 of the canals toward the exterior. Prof. Herrick's statement, 

 therefore, that the canals of Menidia are degenerate may by no 

 means be improbable. 



