S44< PKACTICAIi AND SCIENTIFIC ZOOLOGY. 



should be here used^ to avoid all confusion in the mind 

 of the student. 



(424.) By Class is implied the first divisions of a sub- 

 kingdom. The vertebrated animals are first divided 

 into classes, whicli Mr. MacLeay was the first to desig- 

 nate and define by their true characters : this name, 

 therefore, is appropriated to those divisions which re- 

 spectively contain quadrupeds, birds, reptiles, amphibia, 

 and fishes: these are the classes of the sub-kiiigdom Ver- 

 tebrata. Those of the annulose animals, on the other 

 hand, have never yet been correctly made out ; it will, 

 nevertheless, be our object, hereafter, to prove that the 

 Ptilota, or winged insects, iheAptera, or wingless insects, 

 the Cirripeda, or barnacles, the Vermes, or worms, and 

 the Annelides, or red-blooded sea-worms, are so many 

 classes, or first divisions of the sub-kingdom Annidosa / 

 representing, of course, those of the vertebrated circle. 

 The classes of the other sub-kingdoms have never yet 

 been defined with precision, nor will it be necessary, in 

 this place, to cite further instances of this description of 

 groups. 



(425.) Orders come next in rank to classes. Looking 

 to the class of quadrupeds, we find there are five natural 

 orders, following each other, however, in a somewhat dif- 

 ferent series to what has been stated elsewhere.* In 

 birds, again, the same groups occur, and they have been 

 correctly designated in the following natural seriesf: — 

 1. Raptobes, or birds of prey; 2.lNSESsoBES,or perch- 

 ers; 3. Rasores, or fowls; 4. Grallatobes, or waders ; 

 5.Natatores, or swimmers. The first division?, also, into 

 which both the apterous and winged insects are naturally 

 grouped, are strictly classes ; of which Linnseus, indeed, 

 seems to have had an intuitive perception ; his Cole~ 

 optera, Hemiptera, Neuroptera, &c., being truly groups 

 of this value, notwithstanding the dismemberment they 

 have received from some of the best modern entomo- 

 logists. In hke manner the Acephala, or bivalves, and 

 the Gasteropoda, or univalves, among the molluscous 

 * Xiinnxan Transactions. f Ibid. 



