LoEB, Optic Vesicles of Nectio-us. 465 



made are a part of the private collection of Professor A. C. 

 Eycleshymer, to whom I am indebted for their use, and for 

 valuable assistance. 



Bibliography. 



1. Balfour, F. M., and Parker, W. N. 



On the Structure and Development of Lepidosteus. Pliil. Tr. London, 

 Vol. XLVI (1882), pp. 359-442. 



2. Eigenmann, Carl. H. 



The Eyes of the Blind Vertebrates of North America. V. The History 

 of the Eye of the Blind Fish Amblyopsis from its Appearance to its 

 Disintegration in Old Age. Mark Anniversary Volume {Ne-M York: 

 Henry Holt) 1903, pp. 167-204. 



3. Kerr, J. Graham. 



The Development of Lepidosiren pa»adoxa. Part III. Development of 

 the Skin and its Derivations. Quart. Jottr. Micr. Sc, London. Vol. 

 XLVI (1902), pp. 417-454- 



4. Marshall, A. M. 



Vertebrate Embryology. (London : Smith, Ehh-ed cf Co.) 1893, pp. 1-621. 



5. Wilson, H.V. 



The Embryology of the Sea Bass (Serranus atrarius). Bull. U. S. Fish 

 Com. Vol. IX ([899), pp. 209-277. 



EXPLANATION OF FIGURES. 



LIST OF ABBREVIATIONS. 



e.c. — ectodermal cells. 



I.e. — cells in lumen of neural canal. 



l.n. — nuclei in lumen of neural canal. 



n. — nuclei. 



n.c. — cell in wall of neural plate or tube. 



n.n. — nuclei in wall of neural tube. 



n.J). — neural plate. 



o.v. — optic vesicles. 



p. — projection of nucleus. 



y.c. — yolk cells. 



y.g. — yolk granules. 



PLATE V. 



Fig. I, represents a transverse section of a 1 2-day embryo of Necturus 

 through the anterior portion of the cephalic neural plate. 



Fig. 2, represents a transverse section of a 14-day embryo of Necturus 

 through the region of the Anlagen of the primary optic vesicles. 



Pig- 3i represents a transverse section of a 16-day embryo of Necturus 

 through the primary optic vesicle. In this stage the neural folds have approxi- 

 mated, but are as yet not closed. The optic vesicles and the neural groove are 

 filled with cellular structures. 



