Lesaon X.] 



NATfUAL HISTORY. 



1 13. T. Why have the Annelides been 

 separated from (he other three classes ? 



P. Because they have red blood, and 

 are the only invertebrate animals that have. 

 The circulation is douhle, consisting of 

 arteries and veins; almost all of them live 

 in water, except the earth-worms. The 

 body, which is more or less elongated, is 

 always divided into little rin^s, whence 

 the name (the Latin word annetltu signify- 

 ing a little rinp), and they respire by 

 which are either spread over the 

 of the body, concealed internally, 

 ioped externally. 



m. T. How are the Annelides di- 



P. Into three order*, the first of which 

 is called the Tt'Blcot^E, or worms inhabiting 

 tubes. Some of these animals form tubes 

 of fragments of shells, sand, and mud, 

 which are lined by a membrane; others 

 form an uniform calcareous tube ; and o:h< rs 

 have their tubes composed of membrane 

 only. 



T. What is the name of the 

 second order ? 



/' The DORSIBRANCIIIATA. 



- ime their peculiarities. 

 /'.They have their bronchia or gills 



distributed about the body, espe- 

 cially the middle portion. The Ar 

 have beautiful little gills in tufts upon the 



middle part of ti ry fifth ring 



larger than the others, and the feet 

 and gills attached to it. In the same or- 

 der we have the Nereids, and many other 

 1 curious and interesting genera. 



1 17. 7' -\\ h t is the name of the third 

 order of Annelidrt f 



ABHANCHIA. This order of animals 



is destitute of external respiratory 



and they M-CIM t<> 



surface of the skin, or, a* in the letc 



intern*! 



some have bristles, j and others ar. f them, they 



moving. I 



di.-idnl into t --\ 



^fffmlm Contorlnplicata, with a portion of the body protrudtd from UM 



* tub* of *nd n I fr.imrnt of (hells. 

 4. \l. ArrnKoin fUcatotmm, . \ lul 



