369 



name which lie himself has previously definitely assigned to such an 

 ossicle -|- a true cranial bone. Then he assumes as probable, not only 

 that an organ that lies, in Amia, anterior to the point where the intra- 

 orbital and supraorbital canals anastomose, lies, in Gadus, posterior to 

 that point, but also that this latter organ, in Gadus, loses its connection 

 with an ossicle in relation to which it was developed and shifts back- 

 ward into a new and secondary relation to another ossicle. It is ac- 

 cordingly evident that Cole does not accept, for the sense organs of 

 the lateral line canals, the same "remarkably constant" relations to the 

 bones of the skull of fishes that he accepts for the sensory canals 

 themselves (p. 133). This is an important distinction, and detracts 

 greatly from the value of his statement on p. 183, that, "It is possible 

 that facts like this (and there are many others) show, that each sense 

 organ had originally its own supporting ossicle"' ; a condition I had 

 definitely shown to exist in young larvae of Amia (No. 1, p. 496). 



On p. 183 Cole says: "Here it is at once obvious that the first 

 organ of Amia situated in the squamosal (= the glossopharyngeal or- 

 gan Xo. 17 infra-orbital Allis) is absent in Gadus." 



This conclusion seems to me a somewhat hasty and too positive 

 one. Organ 3 of the lateral canal of Gadus is the most anterior one 

 that, in that fish, lies in the main sensory line and is innervated by 

 the lateralis vagi. It lies somewhat in front of the lateral end of the 

 supratemporal commissure, is found in approximate relation to an os- 

 sicle that lies mainly anterior to that commissure, and is considered 

 by Cole as the probable homologue of organ 18 infraorbital of Amia. 

 In Scomber the most anterior organ of the main line that is innervated 

 by the lateralis vagi lies enclosed in the hind end of the squamosal. 

 This organ in Scomber thus corresponds, in innervation, with organ 3 

 of Gadus, and, in position, with the glossopharyngeal organ of Amia, 

 facts which certainly indicate the possible, or even probable, homology 

 of the organs in the three fishes. 



On p. 171 Cole, after referring to a certain part of Pollard's 

 work on Siluroids, and to certain of my remarks regarding it, says : 

 "Allis, unfortunately, is not consistent on the point. He disbelieves 

 in the canal as a lateral line structure in Polypterus. but accepts as 

 siuh exactly the same canal in Clarias and Auchenaspis, without con- 

 sidering the possibility of the innervation of it in the latter forms 

 having been erroneously described." 



The canals here under consideration are certain canals referred to 

 by Pollard (Nos. 19 and 20) as a "mucous canal at the base of the 

 loisal fin" in Clarias, "a dorsal canal" in Auchenaspis, and a "com- 

 plete canal in Polypterus" "represented in Amia by the dorsal line of 

 pit organs". These several descriptions of these canals, and I have 

 quoted all that is said about them excepting only their supposed in- 

 nervation, were considered by me so incomplete that I preceded the 

 statement of the homology I proposed for those in Clarias and Auchen- 

 aspis by the word -probably": a qualification wdrich renders the word 



