28 ANIMAL PARASITES AND MESSMATES. 



In the same association we also find the Liriope, a 

 little isoiDod crustacean, of which much has been said, 

 but which for a long time obstinately resisted all 

 attempt at observation. 



This latter personage is an isopod crustacean, of 

 moderate size, which chooses the Peltogaster as a place 

 of abode, after having undergone a very curious regressive 

 metamorphosis. In fact, the young lyriope has at first 

 its little feet like other isopods, but in the adult state, 

 the female loses her antennae, and changes her buccal 

 as well as her branchial appendages, so as to assume a 

 different appearance. Several naturalists have already 

 endeavoured to give the life-history of this singula.r 

 Bopyrian. The illustrious Eathke of Konigsberg dis- 

 covered it; Professor Lilljeborg, of the University of 

 Upsal, gave the first account of it; and finally Professor 

 Steenstrup of Copenhagen made known its true origin. 

 In short, the Lyriopes are Bopyrian Isopods, living 

 oil cirrhipedes (Sacculinidese) as real messmates, if not 

 as parasites ; the male preserves his dignity and his 

 prestige, but the female strips herself of all the attri- 

 butes of her sex, and descends to the lowest degree of 

 servitude. 



Faujas de Saint-Fond has mentioned a fossil hermit- 

 crab as found in the mountain, St. Pierre de Maestricht; 

 but he called by this name a crustacean of the genus 

 Callianassa and not a pagurus. These Callianassie are 

 always completely isolated in the chalk, and it is pro^ 

 bable that they have no other domicile than the sand or 

 ooze at the bottom of the sea, in which they hollow 

 out galleries for themselves. Lobsters act in the same 

 manner after moulting. The Gebim live like the Callia- 



