698 F. W. GAMBLE AND F. W. KEEBLE. 



Fig. 35. — A, B, C, a " chromatophore" from a full nocturne ; A at 6.44 p.m., 

 B at 6.485, C at 6.56. At 7.10 there was no further obvious change. In 

 this case the expansion of the red and retraction of the blue took place slowly 

 and only to a limited extent. Such is often the case with nocturnes in 

 December, though cases of rapid recovery are not rare. December 18th, 

 1898. Camera lucida. 



Fig. 36. — A — F exhibit a series of changes in the same "chromatophore," 

 though the prawn under examination was undoubtedly dead after B was drawn 

 as far as could be ascertained by the stoppage of the heart and gill-current. 

 The pigments were red and yellow. August 25th, 1898. Leitz, oc. 4, obj. 5. 

 camera lucida. 



Fig. 37. — A — C, camera drawings of a " chromatophore " at intervals of five 

 to ten minutes. The specimen was an Hippolyte of a transparent greyish 

 colour when its eyes were amputated at 3.25 p.m., August 25th. Up to 6.10, 

 when sketch A was made, the prawn was kept in the dark. When brought 

 out it was a nearly full nocturne, though greenish blue in tint. While being 

 drawn it recovered (owing to the expansion of its " chromatophores ") to a 

 transparent brown tint, and was undoubtedly alive at 6.40 when the sketches 

 were finished. This shows that amputated Hippolyte nocturne and recover 

 just as normal specimens do. Pigments red and yellow. Leitz, oc. 4, obj. 5. 



Fig. 38. — A — C, camera drawings of the same " chromatophore " from a 

 transparent brown-barred "fascigera" variety of H. varians ; A at 2.16 

 p.m., August 23rd, 1S98, B at 2.18, C at 2.20. These show rapid expansion 

 of pigment into hitherto colourless processes. Leitz, oc. 4, obj. 5. 



