THE AUSTRALIAN MUSEUM MAGAZINE. 



57 



Quaint Crustaceans. 



By F. a. McNkill. 



Among the less liiglily organised 

 members of the various gTOups of ani- 

 mals we will often find curious and 

 wonderful adaptations, whilst deeds of 

 great perseverance are of no less fre- 

 quent occurrence. Many of the crabs 



Sargasso Crab on floating weed. 



Photo — -C. Chitton. 



are highly specialised in these directions, 

 and some cases are quoted below. 



As an instance of how far some crabs 

 travel, and to wdiat extent they wander, 

 -we can take the distribution of the little 



Sargasso or Gulf-weed L'ralj and try to 

 throw some light on this subject. As 

 its name {Planes) implies, it is essen- 

 tially a wanderer, being found in all 

 warm and temperate seas, associating it- 

 self with floating inanimate objects, and 

 is often found on the carapace or shell 

 of large marine turtles. It never 

 approaches land except as the result of 

 misadventure, when it is often unfor- 

 tunate enough to be cast ashore by 

 heavy seas, and is not uncommonly 

 found on the beaches near Sydney, to- 

 gether with the barnacle-covered beams 

 or driftwood which it had selected as 

 its ocean residence. At the mercy of 

 the currents in the open ocean, one in- 

 dividual of this small species may, in 

 all probahility, circumnavigate the globe, 

 rivalling any representative of its kind 

 in the extent of its travels. It is re- 

 corded that the strictly pelagic habits of 

 the Sargasso Crab deceived Columbus 

 during the first voyage he made on the 

 discovery of the West Indies, by con- 

 vincing him that its presence on the 

 Sai'gasso weed {Sargasso bacciferum) 

 floating on the sea denoted the proxim- 

 ity of land. It is probable, however, 

 that the great discoverer utilised the 

 cral)'s presence as an argument to en- 

 courage his despairing sailors, and it 

 was not quite so much to the point as 

 the sailors appear to have tliought it. 



The Marsupial Crab; fig. 1, is a dorsal view of the female 2i times natural si^^. ^8- J J^ 



a side view of the female, showing the pouch- lake abdomen filled with eggs, fig. 3, ventral 



view of female to show the great lateral expansion of the abdomen; fig. 4, dorsal view of 



male, 4i times natural size. Drawing— F. A. MciNeill. 



