PLATE LXIX. 



Astronvdheit uiger. 



Fig. 1 . Lateral \aew, showing the disposition of the Unninous organs : natural size, from a spirit 



specimen. 



a, a, Compouud organs ; b, simple organs ; c, luuiiuous patcli on the side ; d, uu the forehead ; e, «■', on 

 tlie upper jaw. 



Fig. 2. Transverse section through the ventral side. x 10. 



'(, Conipouud luiiiiiious organ ; b, simple luminous organ ; /, intestine ; o, cartilage; V, blood-vessel. 



Fig. 3. Compound luminous organ, from vcntr.il side. Longitudinal section. x 100. 



i, comoa-shaped transparent part of skin over the organ ; t, transparent membrane outside the lens- 

 shaped body ; d, lens-shaped body ; c, gland-tubes of the sphcriial part : /, pigment -layers ; g, ^, 

 pigment coating of the outer and inner parts of the luminous body ; h, gland-tubes in the outer 

 j)art of the luminous orgau ; k, granular mass of secretion and cell.s, inner portion belonging to the 

 glands of the inner part of the organ ; /, giauular mass of secretion and cells, outer part ; m, shining 

 membrane within the pigment-mantle of the organ ; n, ganglion cells in the granular central disc. 



Fig. 4. Diagrammatic section through the axis of the compound luminous organ. x lUO. 



«,, u,,, «3, Bj, 4;, 4.J, 4a, ^4, Kays of light emitted from the central part of the orgau {kj and retlecled in the 

 lower spherical portion of the organ ; c„ c.,, Cj, rf,, d„, (/„ <•], c„, Cj, J\, /„, /j, rays of light emitted from 

 the central ))art of the organ (k), in a centrifugal (lirection, retlected from the sides of the outer 

 parabolic portion of the orgau and refracted by passing through the outer surface of the cornea- 

 like layer (y); Ax, axis of the optical system ; </, cornea ; h, phosphorescent tissue of the outer 

 jiarabolic part ; t, glands of the inner spherical part. 



Fig. 5. Longitudinal section of a simple luminous organ. x 150. 



a. Mass of granular secretion and cells ; b, radial gland-tubes ; c, pigment-mantle ; d, cornea ; c, re- 

 llecting membrane. 



Fig. 6. Section of a lateral luminous patch {c, tig. 1). x iO. 

 a, Pigmented skin of the tish ; b, vertical gland-tubes. 



Fig. 7. Section of a lateral luminous organ. x 4. 

 a. Phosphorescent gland. 



Fig. 8. Vertical section of a lateral luminous organ. x 150. 



a. Granular secretion with cells ; h, gland-tubes vertical to llic skin ; c, pigment-layer ; d, lamella' of 

 pigment, extending U|iwards between the gland-tubes. 



Fig. 9. Section through outer portion of simple luminous organ, x 300. 

 Fig. 10. Simple luminous orgau, seen from without, x 30. 



Fig. 11. Head in profile, x 4. 



a. Frontal phosphorescent gland : 4, anterior, c, posterior infraorbital phosphorescent glands ; rf, ocellar 

 phosphorescent organs. 



Fig 12. Transverse section of narrow posterior end of anterior infraorbital phosphorescent gland. x 150. 

 rt. Transparent outer skin. 



Fig. 13. Longitudinal section of anterior infraorbital gland, x 100. 

 a, Transparent outer skin. 



Fig. 1 I. l'<jrtion of the section figured in fig. 13, showing a gland-tube, x 600. 



II, Membrane of the gland-tiihe ; A, gland-cells : i\ lumen of the gland-tube, tilled with secretion ; rf. » 

 thread of cartilage. 



