28 ARTHUR DENDY. 



12. Studnicka. — " Ueber den feiueren Ban der Parietalorp;ane von Petro- 

 myzon marinus, L," 'Sit.zungsber. der Konigl. bolimisclien Gesell- 

 scliaft d. Wissenscbafteii,' Prag, 1899. 



EXPLANATION OF PLATES 1 & 2, 



Illustrating Professor Arthur Dendy's paper " On the Parietal 

 Sense-organs and Associated Structures in the New 

 Zealand Lamprey (Geotria australis). 



Explanation of Letteeinq. 



At. Atrium of pineal organ. C. Cerebellum. C.U. Cerebral hemisphere. 

 C.U.S. Commissura habenularis (=C. superior). CM. Corpus niammillare 

 (= lobus infundibuli). C.P. Posterior commissure. C.T. Connective tissue. 

 C.T.C. Connective tissue wall of cranium. C.T.N. Nuclei of connective 

 tissue cells. C.T.N'. The same in nervous layer of retina of pineal organ. 

 C.T.P. Parietal plug of modified connective tissue overlying the parietal 

 sense organs. Cr.5'. Connective-tissue sheath, ^/j.^". Ependymal epithelium. 

 Ep.G. Ependymal groove. Epid. Epidermis. G.C. Ganglion cells. G.H.J. 

 Anterior division of left habenular ganglion. G.H.L. Posterior division of left 

 liabenular ganglion. G.H.R. Right habenular ganglion. Inf. Infundibulum. 

 I.S.P.C. Inner segments of pigment cells. L.M. " Limiting membrane." 

 L.M.B. Left bundle of Meynert. Z.P.^. Parapineal organ (= left parietal 

 eye). L.T. Lamina terminalis. Med. Medulla oblongata. Muse. Muscle. 

 Na.C. Nasal cartilage. N.C. Nerve cells. N.C.C. Nuclei of columnar cells 

 of pellucida. N.F.N. Network of nerve fibres, etc. Not. Notochord. 

 N.P.C Nuclei of pigment cells. N.S.C Nuclei of sense cells. Oc.C 

 Occipital cartilage. O.Ch. Optic chiasma. O.L. Olfactory lobe. O.N. 

 Olfactory nerve. O.S.P.C Outer segments of pigment cells. Par.C 

 Parachordal cartilage. P.B. Pituitary body. Pell. Pellucida. Pig^., Pig^. 

 Outer and inner pigment layers of integument. Pl.Ch. Choroid plexuses. 

 P.M. Pia mater. P. N. Pineal nerve. P.N^'^. Branches of pineal nerve. 

 P.S. Pineal stalk.' P.St. Protoplasmic strands in interior of pineal organ. 

 Ret. Retina. R. F. Reissner's fibre. B.F'-'". Constituent branches of 

 Reissner's fibre. R.I.P. Recessus infrapinealis. R.M.B. Right bundle of 

 Meynert. i2. P. Recessus prae-opticus (= R. chiasmaticus). jR.P.iS". Pineal 

 organ (= right parietal eye). R.P.O. Recessus post-opticus. R.S.C. 

 Retinal sense-cells. S.C. Shrinkage cavity above posterior commissure. 

 S.C.K. Terminal knobs of sensory cells of retina. Sept. Longitudinal septum 



