PLATE LXXIII. 



Figs. 45-48. Uahhtaurus marrorhir. 



Vi^. 45. Transverse vertical section of the glandular phosphorescent organ below the gill-cover. x 1 5. 

 a, Granular substance : b, vertical threads ; c, structureless reflecting cuticular membrane : d, pigiuent- 

 layer. 



Fig. 46. Transverse vertical section of the .same organ. x ibi). 



II, Granular substance ; b, vertical threads, consisting of blood-vessels, nerves, aiid a cartilaginous 

 support ; c, structureless reflecting cuticular basal membrane ; el, pigment-layer ; f, outer pavement 

 epithelium. 



Fig. 47. Tripolar cell from the granular substance. x 600. 



Fig. 48. Bipolar cell from the same. x 600. 



Figs. 49-53. Xenodermichtlty^ nudiilosUK. 



Fii^'. 49. Transverse vertical section of the ducts of the slime-glands in the sides of the body. x lOU. 

 a, Outer pavement epithelium with scattered pigment ; 0, proximal end of efferent duct ; f, thick pig- 

 ment-layer of the dermis ; d, transparent fibrons tissue. 



Fig. 50. Axial section of a projecting ocellar phosphorescent organ, from the side of the body. x 100. 

 /(, Thick pigment-layer of the dermis ; h, outer pavement epithelium, with scattered pigment; c, thick 

 pigment-layer covering the upper proximal portion of the organ ; d, internal crest dividing the 

 organ into a proximal and a distal portion ; e, limit of the pigment cover ; /, nerve passing into the 

 organ ; (/, thick pigment-layer on the proximal .side ; h, proximal gi-anular portion, with large nuclei ; 

 i, typical phosphorescent clavate cells ; /.-, pigment patches ; I, transparent epithelium. 



Fig. 51. Bipolar cell from the tlistal portion of the same organ. x 800. 



Fig. 52. Typical phosphorescent clavate cells, from the same. x 800. 

 a. Light-refracting vesicle ; b, nucleus ; c, peduncle. 



Fig. 53. A similar clavate cell witli abnormal refractive vesicle, from the same. x 800. 

 a, Two light-refracting vesicles ; b, nucleus ; c, peduncle. 



Figs. 54-64. Halosaurus macrochir. 



Fig. 54. Surface view of the reflecting membrane, clothing the spaces between the modified scales of the 



lateral line. x 1400. 



Fig. 55. Transverse section of the large lateral slime-canal. x 150. 



a, Phosphorescent tissue overlying the .slime-canal ; b, gland-tubes ; c, sj^ort cylindrical longitudinally 

 .situated cells, with well-defined cell-wall, occupying the lower portions of the slime-canal ; d, irre- 

 gular cells surrounding the lumen of the slime-canal ; c, lumen of the slinie-caual ; /, muscular hbres. 



Fig. 56. Tripolar cell, from the slime-caual; adjacent to the lumen. x 400. 

 Fig. 57. Bipolar cell, from the same situation. x 400. 



Fig. 58. Group of cells, from the slime-canal ; adjacent to the outer wall, hi transverse section. x 500. 

 Fig. 59. Coiled gland-tubes, from tlie vicinity of the slime-canal. x 300. 



Fig. 60. Longitudinal section of the tissue occupying the spaces below the large modified scales of the 

 lateral line. x 500. 

 a. Lenticular yellow bodies ; b, intervening hbrous tissue. 



Fig. 61. Longitudinal section through the slime-canal, showing the i>ho»pliorescent organs, in the modi- 

 fied lateral line. x 150. 

 a. Muscular fibres ; li, inner portion of the tissue filling the slime-canal ; c, lumen of the slime-canal ; d, 

 extensions of the lumen below the inner margin of each scale ; c, extension of the roof of the slime- 

 canal along the outer side of the proximal portion of each inodified scale ; f, tissue covering the 

 slime-canal ; y, tissue between the modified scales of the lateral line ; h, roof of the slime-canal ; 

 (, modified scales of the lateral line ; I; posterior margin of the scale ; I, pigmented membrane 

 covering the outer surface of the modified scales ; m, pigmented membrane covering the inner 

 surface of the modified scales ; n, reflecting membrane on the inner side of the modified scales : 

 0, reflecting membrane on the outer side of the modified scales ; p, phosphorescent organ on the 

 outer side of the scale ; q, transverse ridge of the scale ; /■, inner membrane ; s, outer membrane ; 

 t, canal passing through the scale and leading to the phosphorescent organ. 



Fig. 62. Longitudinal section of a portion of the lateral line, near the proximal end of one of the 



modified scales. x 400. 



II, Phosphorescent tissue overlying the slime-caual ; b, reflecting membrane ; c, pigmented membrane 



below the scale ; d, scale ; c, pigmented membrane ; /, reflecting membrane above the scale ; 



</, extension of the roof of the slime-canal along the outer side of the proximal portion of the scale ; 



h, fibrous tissue ; (', lenticular yellow bodies of the tissue between the scales. 



Fig. 63. Longitudinal section of the slime-canal, showing the phosphorescent organs in the modified 

 lateral line. x 60. 

 rt. Lumen of the slime-canal ; b, tissue of the slime-canal ; c, tissue between adjacent modified scales ; 

 d, scales and their membranes (compare fig. 62). 



Fig. 64. Transverse section of a phosphorescent organ attached to the outer side of the scale. x 400. 

 a, Blood-vessels : b, ganglion cells ; c, phosphorescent spindle c'ells ; d, granular superficial layer. 



