o04 MR PHILIP J. WHITE ON THE 



LITERATURE CONSULTED. 



Dr Carl Gegenbaur. Untersuchungen zur Vergleichenden Anatomie der Wirbelthiere. Das Kopfskelet der 

 Selachier, ah Grundlage zur Beurtheilung der Genese des Kopfskeletes der Wirbelthiere, 1872. 



Dr H. G. Eronn's Klassen und Ordnungen des Thier-reichs. "Der Schadel." — "Das Visceralskelet." 1876. 



W. K. Parker, F.R.S. On the Structure and Development of the Skull in Sharks and Skates. Transactions 

 of the Zoological Society of London, 1879. 



T. Jeffery Parker. A Course of Instruction in Zootomy. "The Skate." 1884. 



Marshall and Hurst. Practical Zoology. " The Dog-fish." 1888. 



INDEX TO PLATES. 



Plate I. 



Fig. 1. Dorsal view of the skull and visceral skeleton. 



Fig. 2. Ventral view of the skull and visceral skeleton. 



Fig. 3. Ventral view of the skull. 



Fig. 4. Side view of the skull. 



Fig. 5. Vertical longitudinal section of the skull in the mesial plane. 



Plate II. 

 Fig. 1. Upper and lower jaws. 

 Fig. 2. Portion of the third branchial arch. 

 Fig. 3. Hyoid and branchial arches laid out. 



Fig. 4. Cerato-branchial of the fifth branchial arch and rudimentary gill rays. 

 Fig. 5. Eye-stalk. 

 Fig. 6. Cartilaginous sclerotic. 



Note. — All the figures, with the exception of Figs. 4, 5, and 6, PI. II., which are natural size, are one- 

 third of the natural size. 



Figs. 5 and 6, PI. II., are from a shark twelve feet long, and all the other figures are taken from specimens 

 from six to seven feet in length. 

 A. Basal angle. 



A/. Foramen common to facial and auditory nerves. 

 An. Antorbital process. 

 Ap. Auditory process. 

 Bl-8. Basi-branchial cartilages. 



h. Strap of cartilage covering ethmoidal canal. 

 B^/3, Br/4. Grooves on third and fourth pharyngo-branchial cartilages. 

 B/i. Basi-hyal cartilage. 

 Bm. Basi-mandibular cartilage. 

 Bp. Basilar plate. 



C. Notochord. 

 Ca. Inner opening of carotid canal. 

 Ca'. Outer opening of carotid canal. 

 C'/. Carotid groove. 

 Co. Occipital crest. 



