56 F. L. LANDACRE 
Norris, H. W. 1913 The cranial nerves of Siren lacertina. Jour. Morph. 
vol. 24, no. 2. 
ReEep, Cartos J. 1916 The epibranchial placodes of Squalus acanthias. The 
Ohio Journal of Science, vol. 16, no. 8. 
Scammon, Ricnarp E. 1911 Normal plates of the development of Squalus 
acanthias. In Keibel’s Normentafeln, Zwélftes Heft. 
Suuutr, H. von W. anv TiLney, FrepEeRiIcK. 1915 Development of the neu- 
raxis in the domestic cat to the stage of 21 somites. Annals of the 
N. Y. Acad. of Sci., vol. 24, pp. 319-346. 
