PLATE LXX. 



Sternoptyx diaphana. 



Fig. 15. The fish seen from the side, natural size; drawn from a spirit specimen. 



'(, Ventral luiniaous organ ; b, anterior, f, posterior lateral luminous organs ; d, anal 

 membrane ; e, submaxillary phosphorescent gland. 



Fig. 16. Submaxillary phosphorescent gland, seen enjaee. x i. 

 a, Mouth. 



Fig. 17. Ventral luminous organ, seen from below. x 2. 

 a, Ventral fins. 



Fig. 18. Vontral luminous organ, longitudinal section, parallel to the mcliau 

 plane of the fish to the side of the mid rib. x 2. 

 n, Central ranal j b, parabolic cups. 



Fig. 19. Ventral luminous organ, outer surface. x 20. 

 a, Projecting mid rib ; h, pigment-mantle. 



Fig. 20. Transverse section of the anterior end of the ventral hirainous organ. 

 X 100. 



o. Projecting cartilaginous mid rib ; h, cartilage thread ; c, crystalline spicules arranged 

 longitudinally so as to reflect the light ; (7, pigment-mantle ; c, main canal ; 

 /, parabolic, paired organs, the apertures of which are covered by a transparent 

 cornea-like membrane ; g, transparent connective tissue surrounding the phos- 

 phorescent tissue. 



Fig. 21. Transverse section through tin? anterior end of the ventral luminous 

 organ. x .50. 



(', Pigment-mantle ; /', light-reflecting layer of spicules ; r, transparent connective 

 tissue ; '/, phosphorescent tissue ; p, transparent outer skin. 



Fig. 22. Postero-lateral luminous organ, seen from the outside. x 30. 



Fig. 23. Longitudinal section of the po.stero-lateral luminous organ, x 50. 



a, Spicules forming a light-reflecting layer ; b, pigment-mantle ; <; large highly 

 stainablc cells at the entrance of the luminous sac ; 'i, gland-tubes. 



Fig. 24. Transverse section through the hemiparabolic reflectors of the postero- 

 lateral luminous organ. x 50. 



", Spicules forming a IJKht-rcflecting layer ; b, i)igment-mantle ; <•, transparent con- 

 nei'tivc tissue ; '/, gland-tubes. 



