138 JULIA WORTHINGTON. 
PAGE 
Trigeminus. : “ ° ; : . 164 
Facialis  . : : : : » 169 
Nerves of the lateral line ; 3 : . ware 
Glosso-pharyngeus : ‘ : s «. 2 
Vagus. : ; : : : - hie 
V. Tue Sprno-occrPITAL AND Sprnat NERVES : : . 174 
INTRODUCTION. 
The species principally used for this investigation was 
Bdellostoma Dombeyi, the ordinary hag-fish of the 
Pacific coast; some points of the gross anatomy, however, 
were worked out from specimens of B. Forsteri, from the 
Cape of Good Hope. There is no difference in the gross 
anatomy of the two species but that of size, and the B. 
Forsteri, being slightly larger, made some of the fine 
dissection easier. 
The investigation of the brain and cranial nerves of 
Bdellostoma was suggested to me by Dr. Howard Ayers, who 
kindly furnished me with a great deal of his own material ; 
and I am glad to have this opportunity of expressing my 
thanks for the interest with which he has assisted and 
directed every stage of the work. I also wish to express 
my thanks to Mr. John G. Koch for his kindness in draw- 
ing for me figs. 1, 2, and 3, and in assisting me with 
fio. 14. 
From the standpoint of the comparative anatomist there 
is interest attaching to a study of the brain of Bdello- 
stoma. ‘The Myxinoid fishes are the most primitive crani- 
ates known, and, to judge from the constitution of their 
central nervous system, they are several degrees lower in the 
scale than their nearest cousins, the Petromyzonts. For this 
reason we have in them a simpler pattern, a more primitive 
or ancestral arrangement of parts than in the higher brains 
previously studied. Moreover, the embryological work of 
Price, 1896, and Dean, 1899, shows that this simplicity is 
