3 68 



system must be regarded as having arisen by the splitting of a single 

 trunk, and the supra - orbital and infra - orbital canals must also have 

 arisen by a similar process ". And on p. 663 : " this observation was 

 confirmed by Beard, who further stated that the supra- and infra-orbital 

 canals arose by the splitting of a single 'branchial sense organ'.'" This 

 origin of the two canals by the splitting of a single trunk canal , or 

 the splitting of a single sense organ is so markedly different from what 

 was observed by me in Amia, that Cole, in these two statements, has 

 certainly not gone far enough. 



On p. 132 Cole gives a list of what he calls "Lateral line os- 

 sicles", and "true cranial bones -j- fused lateral line ossicles". 



In the first of these two lists is found, "Dermal Sphenotic (Amia) 

 = the Postfrontal" : and in the second, "Frontal" and "Sphenotic (most 

 forms) ". By the context it is here clearly evident that Cole assigns 

 to the second of these two categories a bone in Gadus that he has but 

 just described, on a preceding page, under the somewhat ambiguous 

 heading of "Postfrontal or Sphenotic". Turning, now, to his figure 2, 

 PI. 22, it is seen, by the colouring, that Cole considers that both this 

 bone and the frontal are parti}' formed in that same connection with 

 the infraorbital canal that those other bones definitely characterised as 

 lateral line ossicles have with the sections of canal with which they 

 are associated. In this opinion, it seems to me that he is wholly 

 wrong, for neither of the two bones lodges a sense organ of the line 

 here under consideration ; a dermal tubule lies directly opposite the 

 so-called postfrontal or sphenotic, between the adjoining edges of the 

 frontal and pterotic ; and this tubule is the only one found between 

 the organs to which Cole gives the numbers 10 and 11. My ex- 

 perience would, accordingly, lead me to look for no bony tissues of 

 lateral line origin, and related to the infraorbital canal, between those 

 bones of Gadus virens that lodge organs 10 and 11 of the latter line, 

 and I should be led, at once, to homologise Cole's postfrontal or 

 sphenotic with the postorbital ossification of my descriptions of Amia. 

 The postfrontal of my descriptions of Amia I should look for in that 

 ossicle of Gadus that lodges organ No. 10; the double tubule 15 — 7 

 of Amia I should look for in tubule 10 of Gadus morrhua and in 

 tubule 9 of Gadus virens ; and I should ascribe to the frontal, in both 

 of the latter fishes, the same secondary relation to the infraorbital canal 

 that it has in Amia. 



On p. 182 Cole says, of the sense organ that is related to the 

 postfrontal bone of my descriptions of Amia: "Sense organ 14 of Amia 

 in the sphenotic is absent in Gadus, but the course of the otic nerve 

 in the latter form is marvellously suggestive either of its having once 

 existed there, or, what is perhaps more probable that it has shifted 

 backwards and now forms the Ilth sense organ on the pterotic." 



In this apparently simple statement Cole first rejects the name 

 postfrontal, wdiich I had given to the purely lateral line ossicle which, 

 in Amia, lodges organ 14 infraorbital, and substitutes for it another 



