BOOK TWELFTH. 



CEUSTACEA 



CLASSIFICATION. 



§ 262. 



In the Classification of the Crustacea, the remark of Erichson'^^ should 

 be adduced, that, with these animals, the external locomotive organs are not 

 limited, as with the other Arthropoda, to the anterior part of the body» 

 but may exist on all its segments, and often with a shape so changed, that . 

 they become foot-jaws, or anal-feet, or oars. If the Crustacea are ex- 

 amined from this point of view, it will not appear surprising that the 

 Myriapoda are classed among them ; for they do not properly belong 

 either to the Arachnoidae or to the Insecta. 



ORDER I. CIRRIPEDIA. 



Family : Balanodea. 



Genera : Balanus, Chthamalus, Coromda, Tuhicinella. 



Family : Lepadea. 



Genera : Otion, Cirieras, Lepas, PoUicipes. 



ORDER IL SIPHONOSTOMA. 



Family : Penellina. 



Genera : Penella, Peniculus, Lernaeocera, Lernaea. 



Family : Lernaeodea. 



Genera : Achtheres, Tracheliastes, Brachiella, Lernaeopoda, Anchorelloy 



Chondr acanthus. 



Family : Ergasilina. 

 Genera : Dichelestium, Lamproglena, Ergasilus, Nicotkot. 



1 Erichson, Eutomographien, lift. J. p. 12. 



