Plate 6. 

 Figs. 24, 25. Argyropelecus lyelinus Garman. 



Fio". 24. Axial section vertical to the median plane of the iish through an anterior lateral 

 radiating organ. Stained: picric acid-carniin. Drawing; magnified 1 : 84. A, 

 proximal oval part of the organ; li, zigzag fibres of the rellecting layer; C, 

 constriction between the proximal and distal part of the organ; I), distal para- 

 boloidal part of the organ; g, inner region; 1, middle region; p, pigment 

 sheath ; r, retiecting layer ; s, outer region. 



Flo-. 25. The tish seen from the side. Drawing; natural size, a, anal radiating organs ; 

 al, anterior lateral radiating organs; ao, anteorbital radiating organs; br, 

 branchiostegal radiating organs; ml, medial lateral radiating organs ; op, oper- 

 cular radiating organs ; pc, pectoral radiating organs ; po, i)ostorbital radiating 

 organs; vc, ventrocaudal radiating organs ; ve, ventromedial radiating organs ; 

 vt, ventrothoracic radiating organs. 



Figs. 26, 27. Sternoptyx obscura Garman. 



Fig. 26. The fish seen from the side. Drawing ; natural size, a, anal radiating organs ; 

 al, anterior lateral radiating organs ; br, branchiostegal radiating organs ; op, 

 opercular radiating organs ; pi, posterior lateral radiating organs ; vc, ventro- 

 caudal radiating organs ; ve, ventral radiating organs ; vt, ventrothoracic radi- 

 ating organs. 



Fig. 27. Axial section vertical to the median plane of the fish through a ventrothoracic radi- 

 ating organ. Stained: haematoxylin-picric acid-fuchsin. Drawing; magnified 

 1 : 42. g, inner region ; gl, gelatinous tissue occupying the distal part of the 

 organ; I, middle region; p, pigment sheath; r, reflecting layer; s, outer 

 region. 



Figs. 28-30. Cyclothone acclinidens Garman. 



Fig. 28. The fish seen from the side. Drawing; natural size, a, ventroanal radiating 

 organs; ve, ventromedial radiating organs ; vt, ventrothoracic radiating organs. 



Fig. 29. The fish seen from below. Drawing ; natural size, a, ventroanal radiating organs ; 

 br, branchiostegal radiating organs; ve, ventromedial radiating organs; vt, 

 ventrothoracic radiating organs. 



Fig. 30. Axial section vertical to the median plane of the fish through a ventrothoracic. 

 radiating organ. »Stained : haematoxylin-picric acid-fuchsin. Drawing; magni- 

 fied 1 : 520; b, blood vessel leading to the organ; c, connective-tissue capsule 

 within the pigment sheath ; cd, transparent connective tissue forming the super- 

 ficial covering of the organ in the orifice of the pigment sheath ; cr, distal part 

 of the connective-tissue capsule covering the mass of radiating cells outside ; 

 1, cylindrical cells of the outer zone ; m, central part of the organ composed of 

 small irregularly arranged polyedrical cells ; p, pigment sheath ; r, outer part 

 of the organ composed of cells arranged in regular rows ; t, transparent inter- 

 mediate zone. 



