INVERTEBRATA. 407 



tubercles." They swim in the ocean or live in the mud, 

 rarely with tubes. This is an extensive order, and has 

 many genera over the world. 



ORDER III. ABRANCHIATA. 



No visible branchiae, respire " by the surface of skin or in- 

 ternal cavities." Live in water, mud, and moist earth. 

 This order has two families. The first embraces the com- 

 mon earth-worm, Lumbicus terrestris, known to all ; and the 

 second, the genus Hirudo, or Leeches. One species of 

 Hirudo is found in the waters of the mountain. 



The next three classes of animals, form the fifth division 

 of Siebold, or Arihropoda. 



CLASS II. CRUSTACEA. 



This class is separated into two sections, the Malacostraca 

 and Entomostraca,. 



FIRST DIVISION. MALACOSTRACA, group a, " eyes placed 

 on a movable and articulated pedicle." 





 ORDER I. DECAPODA, (Ten-footed.) 



This order embraces the large, and some of them useful 

 crustaceans. They usually inhabit water, and are carnivorous 

 and voracious. 



Family I. BRACHYURA, short tailed. This family em- 

 braces but one genus of crabs. 



Family II. MACROURA, long tailed. Cuvier, with De 

 Geer and Gronovius, fixes this group into a single genus, 

 Astacus. There are several subgenera, which contain the 

 common hermit crab, (Cancer bernhardus, Linn.,) the com- 

 mon lobster, (Astacus marinus,) Homerus Americanus, and 

 the fresh-water crabs, or craw-fish. 



ASTACUS bartonii. Fresh- water lobster, craw-fish. This 

 crustacean is common in all the streams of the mountain. 

 It is said to have " nocturnal habits, concealing itself by 

 day," etc. This does not seem to be exclusively his habit ; 



