INVERTEBEATE ANIMALS. 77 



Group 180.— Families OCYPODID^ andGONOPLACIDiE. 



The Ocypodians, as the name implies, are very swift 

 runners, being nearly always on the strand, where they 

 dig holes, in which for the most part they remain during 

 the day, coming forth to feed at night. They are said 

 to hybernate in holes further from the sea. The species 

 of Gelaswius are remarkable for the enormous size of 

 the claw on one side of the male crab : they live together 

 in pairs in holes on the beach : the large chelsB are 

 used to defend the entrance to the hole.* The Gono- 

 placians are good swimmers, and are generally found 

 in moderately deep water. The species are not well 

 defined : one of the forms occurs in British seas. 

 Estimated number of species : recent, 32 ; British, 1. 

 *n Examples of Curtonotus, Macrophthalmus, &c. 



Sbtcentfj €Mt Case. 



The Mark •[ indicates specimens or other illustrations exhibited in the Cases. 



Group 181.— Family GECARCINID^ and allies. 



This group includes four families, well distinguished 

 by the habits as also by the structure of the animals. 



The ThelphusidcB are fresh-water crabs, living in 

 holes on the banks of rivers. 



* My late friend, Canon Kingaley, describes the demeanour of this Crab as 

 irresistibly ludicrous : " One of bis claw arms, generally tbe left, has dwin- 

 dled to a mere nothing and is not seen ; while along the whole front of his 

 shell lies folded one mighty arm, on which he trusts ; and with that arm, 

 when danger appears, he beckons the enemy to come on, with such wild 

 defiance that he has gained therefrom the name of Gelasimus vocans, 'The 

 Calling Laughable ' : and it were well if all scientific names were as well 

 fitted," (" At Last," vol. ii., p. 89.) 



