632 MR FRANK J. COLE ON THE 



Marshall and Spencer, — would probably have never arisen if Stannius had made a 

 careful examination of the roots of the 5th and 7th nerves of his Chimsera* This, 

 however, he omitted to do in the very form — in fact, as far as we know, the only form — 

 which would have repaid the investigation ; and hence the embryologist stepped in and 

 made a discovery that the anatomist had just, and only just, failed to grasp. The 

 more important facts, therefore, relating to the cranial nerves of the Holocephali 

 are, it is claimed, here recorded for the first time. 



Professor Ewart very kindly fell in with my suggestion that the work should be 

 done at once, and placed his material at my disposal. This consisted of two specimens, 

 one of which, the male, had already been partly dissected, and was only available for 

 the study of the 9th and 10th cranial nerves, of which I made a very careful dissection 

 on it ; from the other, a female, I obtained the greater part of the material upon which 

 the present paper is founded. The length of this specimen, without the lash, was 43 

 cms., and the distance from the anterior median canal, through the eye, to the vertical 

 part of the lateralis canal, 1\ cms. ; whilst its depth, through the eye, was 6^ cms., and 

 just behind the pectoral fin, 8 cms. From material I have examined since, it seems that 

 these two specimens were in an excellent state of preservation. 



My acknowledgements are due to Professor G. B. Howes, of the Royal College of 

 Science, South Kensington, for the very generous assistance I received from him during 

 the Easter vacation of 1896. Besides placing his fine collection of Holocephalan 

 material at my disposal, on which, as far as time permitted, I verified the more im- 

 portant parts of the work, he procured for me, with few exceptions, the whole of the 

 works cited in the Bibliography, which, as will be seen, was no slight service. For this 

 and many other services I desire to return both to Professor Howes and his demonstrator, 

 Mr Martin Woodward, my sincere thanks. The exceptions mentioned above I was 

 enabled to consult through the kindness of Mr B. B. Woodward, of the Natural 

 History Museum, South Kensington. I further have to acknowledge much useful 

 advice given me by Dr Beard of Edinburgh. Finally, I am greatly indebted to my 

 esteemed chief, Prof. W. A. Herdman, F.R.S., for much indulgence and advice during 

 the progress of the work. 



B. Historical, t 



When one considers the interesting position of the Holocephali, and the important 

 facts which a study of their nerves and sense organs might reasonably be expected to 

 disclose, it is indeed surprising to find that, with the exception of a very imperfect 

 account by Stannius, this portion of the anatomy of these animals has been entirely 

 neglected. The first work on the subject was published by Breschet in 1838 (l), who 



* Stannius refers to his specimen as " Chimxra (Calorhynchus) ardica." It is really a Chimsera monstrosa. 

 t Cliimccra monstrosa seems to have been the earliest discovered Holocephalan, and was first described by Clusicjs, 

 exactly 291 years ago, under the title of Gulci genus. 



