367 



Chimaera, is said by Cole (No. 5) to innervate two organs in the same 

 canal. In Selachians in general, according to Ewart's schema (No. 9), 

 that section of canal that is defined by him as temporal, is innervated 

 by the branches of three nerves, the oticus facialis, the glossopharyn- 

 geus, and the lateralis vagi ; while in both Amia and Chimaera it is 

 innervated by a single nerve, the glossopharyngeus in the former fish, 

 and the oticus facialis in the latter. 



It is thus evident that the names of the nerves alone, if given to 

 the canals, would be confusing, and even in comparisons they have to 

 be used with considerable circumspection. 



On p. 202 of his work Cole sa} r s: "Allis in seeking to prove the 

 independence of the supra-orbital canal (which is of course independent 

 as far as innervation proves anything), goes somewhat too far in ad- 

 vancing the developmental independence of the supra-orbital canal from 

 the infra-orbital as proving this point. As the lateral canals, according 

 to his own description, develop in independent segments, each containing 

 a sense organ, his argument proves nothing, especially as there is a 

 dermal tubule at the point of anastomosis between the two canals which 

 involves their independence as a developmental necessity." 



While I may be mistaken in my interpretation of this, to me, 

 somewhat difficult passage, I fail to see why or how I went too far 

 "in advancing the developmental independence" of two canals to prove 

 the independence of one of them ; or why my "argument proves nothing", 

 because of its being based on the complete development of the two canals, 

 when Cole himself states that, what is but a single step in that de- 

 velopment, the presence of a dermal tubule at the point of anastomosis of 

 the two canals, "involves their independence as a developmental necessity". 

 Moreover, that this developmental necessity, to which Cole here calls 

 attention, was thus involved in the presence of the dermal tubule at the 

 place indicated by him, was certainly not even suspected until after I had 

 myself shown how a tubule developed there, as a part of the complete 

 development of the two canals. What possible bearing the fact, that each 

 of i he two canals develops in separate segments, can here have I am wholly 

 unable to comprehend, since the anastomosis of the two canals in Amia 

 is formed by the fusion of complete primary pores and not by that of 

 half pores. This developmental difference, which I consider of funda- 

 mental importance, may not however be so considered by Cole, and 

 he may not, moreover, accept, as strictly applicable to all fishes, the 

 manner of development of the canals that I had shown in Amia. This 

 might be taken as indicated by certain passages in his work on Chimaera. 

 In the summary on p. 674 of that work, for instance, he says: "The 

 superficial ophthalmic and buccal divisions at least of the lateral line 



ramus of the so-called inner buccal nerve of Gadus seems, in fact, to 

 correspond to that terminal and somewhat separate part of the buccalis 

 of Amia that was particularly discussed on p. 514 of my earlier work, 

 and that was there said to be destined to supply the organs of the 

 so-called anterior commissure of the infraorbital canals. 



25* 



