1901.] feilPRAOEBMAL CAlfAli OF CSIM^EA. 185 



Teleosts and one or two Elasmobranclis the nerve to the anterior 

 organ of the main trunk-canal emerges from the brain in con- 

 nection ^yith the glossopharyngeal ; and in Chimcera two organs in 

 the middle of the supraorbital canal are innervated by twigs from 

 the Eamus ophthalmicus profundus of the Vth cranial nerve — 

 apparently the only genuine case of connection between the nerves 

 of the lateral line and the trigeminus. This anomaly in the 

 innervation of the supraorbital canal in Chimcera was discovered 

 by Cole \ and evidently caused him considerable perplexity, for he 

 does his best to minimise the awkwardness of the fact and calls to 

 his aid a suggestion thrown out by Pollard to the following 

 effect: — "I should prefer to say that some nerve-fibres had. 

 struck the path of the profundus but did not belong to it, just as, 

 for instance, in Siluroids the fourth nerve accompanies the pro- 

 fundus, though I think everyone would hesitate to say that the 

 fourth nerve was a branch of the profundus '' ". 



This suggestion, ingenious as it is, cannot without further evidence 

 be said to give us much practical help. In the following note I 

 hope to be able to give that further evidence and to show that Pollard 

 was upon the right track, although the details of the connection 

 between the superficialis and profundus fibres do not exactly 

 conform to the picture that he evidently had in mind. 



During the last few months I have had occasion to dissect 

 three heads of Chimcera mo»strosa for various purposes connected 

 with the Museum, and in all three specimens the branch of the 

 profundus that is said by Cole to innervate two organs of the 

 supraorbital canal was joined after leaving the orbit by two twigs 

 from the Eamus ophthalmicus superficialis of the facial. The 

 figure given below (text-fig. 49, p. 186) is compounded from two of 

 the most satisfactory dissections, in one of which the connection 

 betv\een the nerves, and in the other their further distribution was 

 seen to the best advantage. 



On a level with the anterior border of the interorbital mem- 

 brane, the Eamus ophthalmicus profundus of the trigeminal gives 

 off a branch as described by Cole, which runs in an antero-dorsal 

 direction towards the forehead closely applied to the perichondrium. 

 Shortly after leaving the orbit it divides into two subsidiary 

 branches (A and B). The branch A, after crossing the main trunk 

 of the superficialis VII (at this point embedded in the cartilage of 

 the skull), again divides into two smaller twigs (C & D). The 

 twig C continues in an almost perpendicular line towards the 

 dorsal surface of the head and is lost in the frontal clasper in the 

 male ^, and in the female upon the skin in the corresponding 

 position. The twig D, on the other hand, reunites at an acute 



1 Trans. E. Soc. Edinburgh, xxxviii. 1897, p. 645. 



^ Trans. E<. Soc. Edinburgh, xxxviii. p. 638. 



' In the male specimen, 1 was under the impression that this nerve to the 

 clasper was joined by a filament from the superficialis — iuaking, in all, three 

 connections between the superficialis and profundus, but the dissection was not 

 sufficiently good to be quite sure upon the point. 



