040 MR FRANK J. COLE ON THE 



Chimaera 13 canals are distinguished, and the canal supplied by the buccal nerve is divided 

 into four portions, and further confused with a part of the hyomandibular system. 

 The fact that these 13 canals are only innervated by four nerves must, I think, be held 

 to break down the distinctions which Garman has set up. The general opinion, and the 

 most satisfactory opinion, is, that the only scientific basis upon which accurate results 

 are to be arrived at, is to study either the development or the adult anatomy of both 

 canals and nerves, and that to divorce one from the other can only be prolific of in- 

 accurate and misleading results. This is insisted on by Ewart(58, pp. 65 and 70), who 

 quotes Garman as describing 14 canals in Lsemargus, although these 14 canals are 

 innervated by only four nerves. 



I shall therefore, in the present communication, regard the lateral line system as a 

 single system supplied by a single and i^erfectly independent system of nerves. This 

 system of nerves, as far as is known, must be associated with the facial or seventh 

 cranial nerve, and may be said to consist of the following four trunks* : — 



(1) Superficial ophthalmic, coursing over the eye. 



(2) Buccal, coursing under the eye. 



(3) Hyomandibular, coursing behind the spiracle. 



(4) Lateralis, associated with the vagus. 



D. The Sensory Canals of Chimera. 



The fact that the lateral line system of Cliimsera consisted of open furrows visible 

 for the whole of their length on the surface of the animal was first described, I believe, 

 by Prince Bonaparte in 1846. A further description was published by Costa in 1852, 

 whilst Dumeril, in his Histoire naturelle des Poissons, published in 1865, supplemented 

 the descriptions of Bonaparte and Costa with an account of Callorhynchus, and he was 

 therefore the first to point out the interesting difference between Chimzera and Callor- 

 hynchus in this respect ; in so far as the sensory canals of the latter are formed of 

 closed tubes and not of open furrows. Leydig's work, published in 1851, on the anatomy 

 of the sensory canals (7), has been already referred to. In 1877 Hubrecht (17) re- 

 figured both Chimera and Callorhynchus, and Solger's memoir on the histology of the 

 sensory canals (25, 1880) has been noticed in my historical section. Garman (44) gave 

 still further descriptions and figures of both genera in 1888, and since the publication 

 of this work numerous descriptions and figures of the sensory canals of the Holocephali 

 have been published in text-books and elsewhere (e.g., Day, Bashford Dean and others). 

 One memoir, however, calls for special notice, and that is the description in 1894 by 

 Goode and BEANt of an important new genus of Chimseroids which these authors named 



* I am purposely omitting the great recurrent facial described first by Stannius in Silurus, and recently in 

 many Siluroids by Pollard. I shall refer to it later on. 



t " On Harriotta, a new type of Chimseroid fish from the deeper waters of the North-western Atlantic," Proc. 

 United, States Ned. Mus., vol. xvii. p. 471, 1894. 



