196 A HISTORY OF EECENT CEUSTACEA 



times attaining a length of eighteen inches, and is valued 

 for food, though it has a less delicate flavour than the lob- 

 ster. Though its front legs make a very feeble show in 

 comparison with the powerful chelae of the lobster, when 

 the mandibles are compared the advantage is greatly in 

 favour of the Palinwus, or Crawfish as it is often called. 

 Spence Bate has pointed out that in this genus and its 

 immediate kindred there are button-shaped tubercles on 

 either side of the trunk, which fit into cavities on the under 

 surface of the carapace, and have a very great power of re- 

 tention, this buttoning of the carapace being probably an 

 important protection to the branchiae that are placed 

 beneath it. Its long stiff antennas are said frequently to 

 prevent it from, entering the pots set for catching crabs 

 and lobsters, and thus, while disappointing it in its search 

 for food, indirectly help to save its life. As in Palinurus 

 the ear-stones are introduced, and yet the animal has no 

 claws with which to pick up grains of sand and place them 

 in the auditory cavity at the base of the first antennas, it 

 might well be wondered how the otoliths reach their de- 

 stination ; but Hensen explains that the crustacean has 

 only to burrow with its head in the sand, and the required 

 particles will easily find their way into the ear-chamber. 



[Palinosytus], Spence Bate, 1888, has the rostrum an- 

 teriorly produced so as to reach beyond the ocular segment, 

 and by its connection with the segment belonging to the 

 second antennas forms a channel for the protection of the 

 ocular segment. The first antennas have two short 

 flagella, and their segment is not produced beyond the 

 extremity of the rostrum. This genus belongs at present 

 only to the southern hemisphere. A specimen of Palinosytus 

 Lalandii (Lamarck), ten inches long, was taken by the 

 Challenger near Tristan da Cunha. Also a small specimen, 

 about an inch long, was taken near the Cape of Good Hope, 

 and this in all but sexual character already appeared to 

 have the perfect adult form. Palinost/tus HiigeUi (Heller) 

 is the common Crawfish of Sydney, in Australia, and if, as 

 Haswell supposes, it be the same as the New Zealand 

 Palinurus tumidus, Kirk, it must be credited with attaining 



