F. S. CONANT ON THE CUBOMEDUS-<E. 61 



Fig. 44. Diagram to show relations of sensory niche, of bell margin and 

 velarium in adult Tripedalia. The velarium represented as pendant. 



Fig. 45. To show the same structure in a young Tripedalia. 



Fig. 46. Horizontal section through the last just at the margin, to compare with 

 Fig. 29. 



Fig. 47. Cross-section through the nerve ring. 



Fig. 48. The structure of the nerve as seen by focusing at successive levels. 



Fig. 49. Diagram to show the relation of the nerve ring to the sensory club. 



Fig. 50. Horizontal section through the upper part of the sensory niche, to show 

 passage of nerve root through gelatine of subumbrella to stalk of sensory club. 



Fig. 51. Vertical section through base of stalk of sensory club, to show same 

 passage. 



Fig. 52. Similar section to last, but nearer to perradius,to show sub-endodermal 

 tract of nerve fibres. 



Fig. 53. Sensory organ in proboscis of Tripedalia, as seen from surface in living 

 animal. 



Figs. 54 and 55. Sections of same sensory organ. 



Fig. 56. Vertical section through one side of proboscis, to show sensory organ 

 attached to endoderm. (Tripedalia.) 



Fig. 57. Diagram of the outlines of sensory club seen from the side, by camera 

 lucida. 



Fig. 58. Part of retina of larger complex eye cut radially. 



Figs. 59-62. Four sections in direct sequence through retinal cells transversely, 

 larger eye. 



Fig. G3. Transverse section through the tips of cells of a slightly pigmented 

 retina, larger eye. 



Figs. 64-66. Three transverse sections through vitreous body at different levels. 

 All from same series, but not in direct sequence ; larger eye. 



Fig. 67. Kadial section through retina, to show fibres from the long pigment 

 cells ; larger eye. 



Fig. 68. Transverse section through vitreous body of Tripedalia near retina. 



Fig. 69. Vertical section through smaller complex eye. 



Fig. 70. Wandering cells, Charybdea. 



Fig. 71. Floating mass, from stomach pocket of Tripedalia. 



Fig. 72. Horizontal section through larger complex eye. (See text figure, p. 50.) 



