234 W. BALDWIN SPENCER. 



EXPLANATION OF PLATES XIV, XV, XVI, XVII, 

 XVIII, XIX, & XX, 



Illustrating Mr. Baldwin Spencer's Paper on " The Presence 

 and Structure of the Pineal Eye in Lacertilia/' 



List of Reference Letters. 



Ant. {Le). Cells of anterior wall of distal vesicle of epiphysis. C. Cilia of 

 cells lining epiphysis. Ca. Capsule of connective tissue enclosing the pineal 

 eye. Car. Cartilage within skull in Hatteria. Cb. Cerebellum. C. H. Cere- 

 bral hemispheres. Co. Cone-shaped bodies of pineal eye. Cb.' Modified 

 cone-shaped bodies lying near the pineal stalk. Cor. Cornea. Ct., Ct.^, Ci.^, 

 Ct?, Ct.*, Ct.^, Ct.^ Connective tissue in various positions in connection with 

 the parietal foramen and pineal eye. Ct.pig. Pigment in the cutis vera. 

 Cut. Cuticle. De. Dermis. D. M. Dura mater. Bp. Epidermis. Ep., Ep.^ 

 Epiphysis. Ep. 1. Swollen distal end of epiphysis. Ep.^ (ops.) Portion of 

 epiphysis equivalent to the pineal stalk. Hum. Humour of eye. Inf. Infun- 

 dibulum. Le. Lens. Md. Medulla oblongata. Mes. Mesencephalon. Mo. 

 Molecular layer of eye. N. Nuclei of cells of epiphysis walls. iV.', n.^ In- 

 ternal row of nuclei in retina. n.", N." External row of nuclei in retina. 

 n.^ Specialised nucleated elements in pineal stalk of Hatteria. ne. Nerve- 

 fibres. N. ct. Nuclei of connective tissue. Olf. Olfactory nerve. Op., Op. v. 

 Optic vesicle. Op. S. Pineal stalk. Op. L. Optic lobe of brain. Fa. for. 

 Parietal foramen. Pa., Par. Parietal bones. Post. {R.) Cells of posterior 

 wall of swollen end of epiphysis in Cyclodus. pig., pig}, pig.^, piff-^y V^9* 

 Pigment developed in various positions in connection with the eye. Proc. 

 Processes uniting various retinal elements in Varanus. Re. Retina of pineal 

 eye. R., r. Rods of retina. R.^ Specialised rods in connection with entrance 

 of nerve-fibres. R. Mp. Pete mucosum. S. Spindle-shaped elements of 

 retina. Thl., Th. Zrd vent. Thalamencephalon and 3rd ventricle. Fent.^ 3rd 

 ventricle. 



PLATE XIV. 



Fig. 1. — Longitudinal vertical section through the parietal foramen of 

 Varanus giganteus. The right side lies posteriorly, the left anteriorly, 

 and the parietal bone enclosing the foramen is shaded yellow. The connective 

 tissue is seen forming a dome to the foramen and filling up the latter. The 

 pineal eye is cut through in the median line, showing the lens with its special 

 development of pigment in the optic axis and the retina with the elongated 

 rods where the nerves enter the vesicle. The nerves are three in number, two 



