HIFPOLYTE VARIANS. 



651 



Section VIIT. — Summary of Experimental Eecords. 



Table. 



II 



III 



IV 



Name of 

 experiment. 



Object of 

 experiment. 



Weed colour 



experiment 1. 



Flask A 



Weed colour 



experiment 2. 



Flask B 



Weed colour 

 experiment 3 



Weed colour 

 experiment 4 



Light- 



intensity 



experiment 1 



To test result 



of placing 



H i p p 1 y t e 



of one colour 



with weeds of 



a different tint 



Same as that 

 of Table I 



To test result 



of putting two 



greenish-brown 



Hippolyte 



varians and 



one S pi r onto- 



caris pusiola 



with green 



Zostera 



Two green 



Hippolyte 



placed \yith red 



Delesseria 



in the open 



To test result 



of placing 



freshly caught 



Hippolyte 



under varying 



light 



intensities 



Resalts. 



No evidence that the colour of the weed 

 as such has any effect. Changes of 

 colour, referable in every case to a 

 daily cycle of colour-change, influenced 

 to some extent by the illumination. 

 Irritable condition on Aug. 2nd seen in 

 A, B, and C, followed by rapid changes 

 to and from the nocturnal state of 

 colour. 



Same results. The changes to green and 

 to red noticeable in specimens A and d 

 respectively occur in the dark, and 

 therefore cannot be due to the colour oi 

 the weed, although in both cases tlu 

 change was in the direction of thi 

 colour of the weed. 



The two Hippolyte exhibited rhyth- 

 mical nocturnal changes, and assumed 

 during the day a bright emerald-green 

 and greenish-yellow tint matching the 

 leaves and stalks of the Zostera. 

 These changes took place as well in 

 the dark as in the light (see July 30tli, 

 12.30 p.m., and Aug. 2nd, 10.10 a.m.) 

 and therefore cannot be attributed to 

 the colour of the weed. Spironto- 

 caris remained throughout of a trans- 

 parent bluish colour. 



[n 3^ hours one became brown, and 

 showed expansion of red pigment on 

 being examined microscopically. 



Begun 4.6 p.m. ; examined 7.30 p.m. 

 Dim scattered light produced by 

 covering a porcelain pot with muslin 

 is most favourable to the induction of 

 " nocturnes." A muslined glass jar 

 produces a green colour. Clear glass 

 jar standing exposed to full daylight 

 and black covered jar produce very 

 slight changes in the Hippolyte 

 placed within. [In some of our more 

 recent experiments (1899) nocturnes 

 were found in the black covered jar, 

 but muslined porcelain always is most 

 favourable.] 



