168 CIERIPEDIA. 



undergoing, especially at the second moult, a con- 

 siderable change of figure. At the third moult it 

 has assumed almost the form of a Cypris or Gythere, 

 being inclosed in a bivalve shell, in which the 

 front of the head with the antennae is greatly 

 developed, equalling in bulk all the rest of the 

 body. The single eye has become two, which are 

 very large, and attached to the outer arms of two 

 bent processes like the letters U U , which are seen 

 within the thorax. 



In this stage the little animal searches about for 

 some suitable spot for permanent residence ; a 

 ship's bottom, a piece of floating timber, the back 

 of a whale or turtle, or the solid rock. When its 

 selection is made, the two antennae, which project 

 from the shell, pour out a glutinous gum or cement, 

 which hardens in water, and firmly attaches them. 

 Henceforth the animal is a fixture, glued by the 

 front of its head to its support. Another moult 

 now takes place ; the bivalve shell is thrown off, 

 with the great eyes, and their U-like processes, 

 and the little Cirriped is seen in its true form. It 

 is now in effect a Stomapod Crustacean, attached 

 by its antennae, the head greatly lengthened (in 

 Lepas, &c), the carapace composed of several 

 pieces (valves) presently to be described, the legs 

 modified into cirri, and made to execute their 

 grasping movements backwards instead of forwards, 

 and the whole abdomen obliterated, or reduced to 

 an inconspicuous rudiment. 



As the several valves of which the carapace is 

 formed furnish important characters for discrimi- 

 nating the genera, it will be necessary to name 

 and to explain them. In the stalked or true Bar- 

 nacles [Lepadidce), in which the carapace is seated 



