696 F. W. GAMBLE AND P. W. KEEBLE. 



Fig. 19. — A "chromatophore" from a red-liner, to show the way in which 

 these colour elements frequently wrap their processes round the walls of an 

 artery. The blood-corpuscles are about equal in diameter to the calibre of 

 this capillary. In the chromatophore the two pigments (red and yellow) are 

 distinct, and a point of fusion with a neighbouring pigment spot is indicated. 

 The anastomosing tendency of the branches is here distinct. Leitz, oc. 3, 

 obj. 5. Camera lucida. September 20th, 1898. x 190. 



Fig. 20.— Deep intermuscular chromatophores of a red-liner. Leitz, oc. 3, 

 obj. 6. Camera lucida. August 24th, 1898. x 250. 



PLATE 35. 



Fig. 21. — Right side of the carapace of a green specimen drawn with the 

 camera, to show the varying form and size of the "blue spots." Transmitted 

 light. Leitz, oc. 1, obj. 3. X 30. September 19tli, 1898. 



Fig. 22. — A "blue spot" from a green Hippolyte varians, sending 

 out delicate branches which in close association wi4h the yellow of neighbour- 

 in"- chromatophores produce a total effect of green by reflected light. Each 

 of these chromatophores has possibly its own store of blue colour in addition 

 to the red and yellow seen in the figure ; but it is difficult to determine how 

 much of the blue constituent of the green effect is derived from the branches 

 of the large blue spot, and how much is proper to each chromatophore. 

 Transmitted light. Leitz, oc. 3, obj. 5. Camera lucida. See text, p. 190. 

 September 20th, 1898. 



Fig. 23. — Muscle chromatophores from a small pink Hippolyte varians. 

 The colour of the specimen was almost entirely due to these deep chromato- 

 phores. The red pigment (black in the figure) is arranged in tubes which 

 run parallel to the course of the fibres, and give off branches which pass 

 outwards and bifurcate. The colour of most small Hippolyte is deter- 

 mined by the amount and arrangement of the pigments in these muscle 

 chromatophores. In larger, less transparent forms the superficial network of 

 colour conceals the great store of pigments which exist in the underlying 

 muscle. Leitz, oc. 3, obj. 5. St. Vaast. August, 1899. 



Fig. 24. — A portion of the carapace of a full brown Hippolyte. The 

 network is chiefly red with some yellow strands, and here and there green 

 patches. It is difficult to distinguish " chromatophores." Leitz, oc. 1, obj. 3. 

 Camera lucida. September 16th, 1898. 



Fig. 25. — Blue spots and the indefinite irregular reticulum of a pink 

 Hippolyte. The blue spots have distinct clear envelopes traversed by 

 yellowish radiations, and by three stouter red i)rocesses which arise from the 

 larger blue spot and mingle with the general reticulum. Leitz, oc. 3, obj. 

 5. August 5th, 1898. 



