144 ON THE COCOA-NUT CRAB. 



Ambon our dexterous friend principally follows its thievish 

 practice during the night". Therefore Darwin's ^) assertion 

 »the Birgos is diurnal in its habits", that found its way in 

 many popular handbooks, must be considered to be founded 

 on a mistake and is somewhat in contradiction with his 

 own words that directly follow »but every night it is said 

 to pay a visit to the sea". About these reiterated visits 

 of our crab to the sea, and the reason why this happens, 

 the authors are neither very unanimous ; according to some 

 of them it is »for cooling its thirst", according to others 

 for » moistening its gills" or » deposing its eggs". Mose- 

 ley ') f. i. was informed by an intelligent native at Zam- 

 boanga that »the crabs went down to the sea occasionally 

 to drink". Semon, however, writes: »from time to time it 

 will repair to the sea, a habit attributed by the people to 

 its desire of moistening its gills. Personally, I consider 

 this motive as very improbable. The gills are very small, 

 but the walls of the cavity containing them are covered 

 with a rich vascular network, and act as a sort of lung. 

 Far more likely does it seem that the crab's periodical 

 visits to the sea are simply for the deposition of eggs, etc.". 

 On the contrary Rumphius asserts: »Zij woont in de holle 

 steenklippen, doch altijd op het land, zonder ooit in 

 't water te komen" and farther on »de bovenstaande 

 beurskrabben moet men noch in zout, noch in versch water 

 laten komen, want daar in sterven ze straks". But the 

 greatest disagreement reigns among the naturalists about 

 the question, whether the crab possesses the ability of 

 climbing upon trees. For Rumphius tells us: »zii be- 

 klimt de kalappusboomen, welker nooten zij afknijpt, en 

 de afgeworpene onder den boom naspeurt, enz." and in 

 agreement herewith Forbes writes: »it has a habit of climb- 

 ing the cocoa-nut palms, but whether to take the air or 

 for temporary lodging is doubtful ; it does not rob the 



1) Journal of researches into the Geology and Nat. History etc., 1889, p. 551. 



2) Notes by a Naturalist on the «Challenger", p. 403. 



Notes from the Leyden IMuseum, "Vol. XX.III. 



