302 MANUAL OF NATUKAL HISTOEY. 



The metamorphosis of the Cirrhopods is very curi- 

 ous. The young are hatched from an egg, and re- 

 semble the larvae of Cyclops and other Entomostra- 

 ca; they swim freely about, have two long antennae, 

 three pairs of jointed legs (the hind pair of which 

 is bifid), a bilobed, jointed tail, and eyes. They 

 soon become invested with a coriaceous bivalve shell 

 like that of Gypris, to the sides of which the animal 

 fixes itself by the head ; the shelly valves then make 

 their appearance ; the antennae and eyes disappear ; 

 three more pairs of legs are developed, and the 

 creature finally assumes the shape familiar to our 

 admiring eyes. 



The Cirrhopods have a wide range in their geo- 

 graphical distribution, being found in all seas ; the 

 particular localities in which they occur are ex- 

 tremely varied. Some sessile forms, as the Bala- 

 nidce, live attached to tidal rocks, stones and shells; 

 some, as the A casta of Leach, take up their abode 

 in sponges, and the Catophragmus of Sowerby in 

 coral ; others, again, are found imbedded in Ma- 

 drepores and Fungice, as the genera Pyrgoma, Da- 

 racia, Megatrema and Greusia, while the Conopea 

 of Say is affixed to Gorgonice and horny corals. 

 Some live parasitic in the skins of whales, as the 

 Getopirus, the Tubicinella, and the Diadema ; 

 others, as the Platylepas of Gray, and the Goro- 

 mda testudinarius, Lin., fix themselves upon the 

 backs of turtles ; others have been found on the 

 bodies of sea-snakes ; one, the Asterolepas Icevis 

 of Gray, on the Voluta; and another, the Goto- 



