616 3. Die höheren Lebenseinheiten. 



oder ein anoxybiotischer ist, je nach der zur Verfügung stehenden Sauerstoffmenge. 

 Daher wird von den untersuchten Aktinien selbst in normalem Seewasser ein 

 Teil der Zellen anaerob arbeiten, da sonst keine Veranlassung zur Erhöhung des 

 Konsums vorlag bei Vergrößerung des normalen Druckes. Die Fähigkeit des 

 Sipunculus, in sauerstofffreiem Wasser zu leben, ist auch nur unter der An- 

 nahme anaerober Stoffwechselprozesse möglich. Erhöhung der Temperatur des 

 Wassers ändert den Sauerstoffkonsum kaum. Bei so empfindlichen, zarten 

 pelagischen Tieren wie Pelagia noctiluca ist die Diffusion des normalen Sauer- 

 stoffdrucks bereits vollständig hinreichend, um allen Geweben den maximalen 

 Sauerstoffbedarf zuzuführen. Einer Druckerhöhung folgt hier keine vermehrte 

 Sauerstoffaufnahme. 



Neben dem Sauerstoff die Kohlensäure zu bestimmen, ist experimentell 

 nur schwierig durchzuführen. Die wenigen Versuche zeigen jedoch, daß dem 

 steigenden Sauerstoffkonsum ein proportionales Ansteigen eliminierter Kohlen- 

 säure nicht folgt. Dohrn (Berlin). 



1327) Gamble, F. W. (University of Birmingham), The relation bet- 

 ween Light and Pigment-formation in Crenilabrus and Hippolyte. 

 (Quart. Journ. Micr. Sei. 55,3. p. 541—583. 1 platc. 1910.) 



In this important paper Gamble continues the studies on colour- 

 physiology begun by Keeble and himself (1900 — 1905). The observations 

 were made on the fish Crenilabrus melops (wrasse) and the Prawn 

 Hippolyte. 



In the young wrasse there are four colouring matters, blue, black, yellow 

 and red. The blue colouring matter in contained in the skeleton, and is 

 possibly allied to the green in the skeleton of Belone and the „vivianite" 

 found with some fossil fishes. The yellow and red pigments oeeur in chro- 

 matophores scaltered on the back, flanks, and finrays. The combination of 

 superficial yellow with blue seen from within gives green; expansion of the 

 red chromatophores gives a ruddy or brown tint. Six vertical stripes are 

 produced by bands of red and black chromatophores, which may be expandea 1 

 or contracted so that the bands are more or less conspieuous, a phenomenon 

 more completely seen in some related species. Various Stimuli cause this 

 reaction, which is probably controlled by ganglia of the sympathetic system. 



Experiments were made to test the effect of backgrounds and transmitted 

 light of different colours. The chief results were as follows: — 



Darkness (5 days) produces extreme contraction of all chromatophores. 

 Black and white backgrounds gave (in 3 weeks) dark brown and light (green) 

 tints respectively. Brown sea-weed background acts like black. Both green 

 and red weed background produce the same result, a greenish tint inter- 

 mediate between the effects of white and black. 



Light transmitted through coloured weed produces an entirely different 

 effect from weed backgrounds. Daylight through green weed induced brown 

 colouration with increase of red pigment; through red weed green colouration 

 and increased yellow pigment, i. e. in general pigment of the complementary 

 colour to that of the transmitted light is produced. 



Results in general similar were obtained with Hippolyte varians, 

 namely that monochromatic light falling on the young animals induces the 

 formation of pigment complementary in colour to that of the light, 

 and also to that produced by coloured backgrounds and white light. The me- 

 thods employed are fully described, but it was not found possible by any of them 

 to keep the larvae alive more than ten days. At hatching the chromatophores 

 contain red pigment and a variable amount of diffuse blue. The amount of 



