HIPPOLYTE VARIANS. 697 



Figs. 26 — 28. — Three " chromatophores " from different levels of the same 

 part of the body of a specimen of Hippolyte varians. Fig. 26 is a sub- 

 epidermal pigment cell with red, yellow, and blue pigments. Focussing down 

 •013 mm. (as determined by the distance through which the milled head of 

 the fine adjustment is turned), Fig. 27 is reached, which shows the appear- 

 ance of " chromatophores " lying between muscle-fibres. Focussing "066 mm. 

 deeper, Fig. 28, a deeply placed pigmented element, comes into view. Leitz, 

 oc. 4, obj. 3. 



Figs. 29 — 32. — A series of sketches of the same "chromatophores" at 

 intervals of about ten minutes. They are taken from a specimen of the 

 " fascigera" variety of H. varians, the eyes of which were amputated on 

 August 22nd, 1898. The specimen was left in a current of water (in the 

 dark) till 11.20 a.m., August 23rd. It was then freckled, sandy-coloured, trans- 

 parent, not at all nocturnal. Fig. 29 was drawn at 11.25, Fig. 30 at 11.30, 

 Fig. 31 at 11.45. Fig. 32 is an enlarged view of one of the " chromatophores " 

 iit 11.55. A had two dark red spots (black in the figure), the remainder 

 being clear yellowish green. B was bright I'ed. The figures show that for 

 the first ten minutes after exposure to light the '* chromatophores " (even after 

 extirpation of the eyes) began to expand. At 11.35 the specimen was put 

 back in porcelain dish and covered with black cloth. At 11.45 a certain 

 retraction of the yellow and red pigments in A and B respectively had 

 occurred. At 11.55 the specimen was dead. Figs. 29, 30, and 31 are drawn 

 with Leitz, oc. 4, obj. 3 ; Fig. 32, oc. 4, obj. 5. All camera drawings. 



PLATE 36. 



Fig. 33. — D, four drawings of the same " chromatophore ; " A at 6.2 p.m., 

 B at 6.4i, C at 6.8i and D at 8.13 p.m. They are taken from a 

 nocturne at first rapidly recovering, owing to the stimulus of the trans- 

 mitted light. Owing to slight movements of the animal there are slight 

 discrepancies between the figures, but great care has been taken to represent 

 the same " chromatophore " in each drawing. The red and yellow pigments in 

 A are strongly retracted, while the enveloping blue merges into a delicate 

 blue reticulum. As recovery proceeds the yellow pigment comes out, followed 

 by the red, while as the blue retracts from the reticulum it forms irregular 

 masses at the sides of the " chromatophore." The pigment is very granular, or, 

 what is probably a more correct statement, there are bodies of peculiar optical 

 properties bathed in a homogeneous yellow pigment. When this pigment is 

 beginning to expand these bodies are carried outwards, and at first have very 

 little pigment with them. Tliey then appear dark by transmitted light, but 

 bright yellowish by reflected light. Leitz, oc. 4, obj. 5. Camera lucida. 

 December 21st, 1898. 



Fig. 34.—" Chromatophore " of a nocturne, to show retracted red and yellow 

 and expanded blue pigments. Zeiss, oc. 4, obj. D. Camera lucida. 



