28 



lepadim:. 



end of the whole animal. The accompanying woodcut 

 gives at a glance, a view of the homologies of the exter- 

 nal parts : the upper figure (from Milne Edwards) is a 



Ml I i 



t ■ 



[w. — Mouth.] 



Stomapocl Crustacean, Leucifer of Vaughan Thompson, 

 and the abdomen, which we know becomes in Cirripedes, 

 after the metamorphosis, rudimentary, and therefore does 

 not fairly enter into the comparison, is given only in 

 faint lines : the lower figure is a mature Lepas, with 

 the antennae and eyes, which are actually present in the 

 larva, retained and supposed to have gone on growing. 

 All that we externally see of a Cirripede, whether pedun- 

 culated or sessile, is the three anterior segments of the 

 head of a Crustacean, with its anterior end permanently 

 cemented to a surface of attachment, and with its posterior 

 end projecting vertically from it. 



CAPITULUM. 



I will now proceed to a general description of the 

 different parts and organs in the Lepadidse. The Capi- 

 tulum is usually much flattened, but sometimes broadly 

 oval in section. It is generally formed of five or more 

 valves, connected together by very narrow or broad strips 

 of membrane ; sometimes the valves are rudimental or 

 absent, when the whole consists of membrane. When 

 the valves are numerous, and they occasionally ex- 



