5i 



Starfishes are not dreaded at Arcachon to the extent 

 they are in England or the United States. Their 

 numbers and the amount of harm they do are incon- 

 siderable in most years and when they do appear it is 

 difficult to say whether the harm they cause is not 

 more than counterbalanced by the good they effect by 

 destroying mussels for which they show a decided prefer- 

 ence, not because they prefer the flavour of the mussel 

 to that of the oyster, but probably because they find it 

 easier to exhaust the former and drag apart its valves. 



The comparative immunity of the Arcachon parks 

 from the attacks of starfishes appears to be due to the 

 fact thai; the beds are not permanently under water. 

 Starfishes do not stand exposure well and are seldom 

 found between tide-marks ; besides, the almost daily 

 attention the parks receive enables the parker to destroy 

 at once any which do find their way into the basin, star- 

 fish being- conspicuous objects when stranded. 



Shell-tunnelling worms (Leucodore) and sponges 

 (Clitme) are met with at Arcachon, but scarcely deserve 

 mention, so inconsiderable is the harm they do owing 

 partly to the high cultivation and cleanliness prevailing, 

 and to the fact that the bulk of the oysters are vended at 

 an early age. No very old oysters are ever kept on hand 

 in the basin and as no accumulation of calcareous rubbish 

 is tolerated in the parks, neither of these foes, which 

 elsewhere sometimes occasion considerable loss, finds 

 favourable life-conditions to multiply at Arcachon. 

 Enemies of this class are as weeds on agricultural land, 

 of no account so long as the fields receive careful atten- 

 tion at the proper seasons but a bane and source of loss 

 whenever vigilance is relaxed. 



Crabs and fishes at the present time give the greatest 

 trouble to the parkers, occasioning heavy loss if adequate 

 protective measures be not continually kept up. The 

 worst offender amongst the crabs is the common green 

 shore-crab, Carcinus mcenas. They occur in great 

 numbers and defy all attempts at extirpation- To mature 

 oysters they can do little or no mischief, a two year-old 



