720 SUMMARY OF CURRENT RESEARCHES RELATING TO 



In regard to Hippolyte varians the amount of larval pigment (which is 

 always red) is constant in any brood, and it is correlated with the 

 amount of red pigment present in the female parent in all colour 

 varieties except green. A given green Hippolyte has one of three types 

 of progeny— all red, all colourless — or a mixed brood, containing red 

 and colourless individuals in a proportion of nearly three to one. The 

 author considers that this suggests that green individuals are of two and 

 possibly three kinds : (1) brown forms that have become green ; (2) 

 green forms that have undergone no change of colour ; and (3) a cross 

 between these two. But in the absence of the knowledge of the male 

 parentage, the last suggestion required confirmation. 



Light is not essential to the production of red pigment in the larva. 

 Darkness does not prevent the continued production of red pigment in 

 young forms. The action of monochromatic light upon the pigment- 

 formation of Hippolyte is entirely different from that of a monochromatic 

 background in white light. In pure red light yellow pigment develops. 

 In some cases this leads to a green coloration, in others the colour 

 remains yellow. In green light a carmine pigment is produced, and any 

 red or yellow pigment existing in the experimental batch is either 

 destroyed or disappears completely. On a red background in white light 

 Hippolyte becomes reddish orange. On a green background in white 

 light Hippolyte becomes green, but the colour is not retained if the batch 

 is transferred to an absorbing dark background. Continued exposure to 

 daylight and a white background produced hypertrophy of the red 

 pigment along the nerve cord and a disappearance of the red and yellow 

 pigment elsewhere. The production of the sympathetic colouring along 

 the shallower zones of the coast is explained as a background effect, 

 in which the incident diffused light plays little part. The influence 

 of background is predominant. The production of crimson colouring 

 in deeper water may be due to diffused green light. There is no 

 evidence that the pigments of the food (Alga?) are the source of the 

 pigments of Hippolyte. 



East African Entomostraca.* — E. von Daday continues his account 

 of the fresh-water micro-fauna in German East Africa, the present 

 instalment dealing mainly with Cladocera and Ostracoda. 



Alleged Mimicry in Acorn-shells.f — A. Joleaud deals with De 

 Allessandri's view that certain details of ornamentation in the shell of 

 Balanus are mimetic. Thus B. mylensis " takes on by analogy or 1 >y 

 sympathy the form of the costules of Isis melitensis" on which it grows. 

 But Joleaud shows that the foundation of the shell and the subsequent 

 zones of increase always accommodate their shape to the undulations and 

 irregularities of what they grow on, and there can be no question of 

 mimicry. 



Protandrous Hermaphroditism in Lernssopodidas.J — A. Quidor 

 finds that in Anchorella, Brachiella, and Lemseopoda, the same animal 

 may be first male and then female. In some cases (as in Nicothoa 



* Zoologica, xxiii. (1910) heft 59, pp. 113-76 (4 pis.). 

 t C.R. Soc. Biol. Paris, lxix. (1910) pp. 101-2. 

 t Comptes Rendus, cl. (1910) pp. 14G4-5. 



