ON ZOOLOGICAL SY8TEMS, AND THE 



their medusas or sea-nettles, actinias or anemonies, and other efflorescent 

 worms, urchins, and star-jGshes ; and thus largely infringing on the mol- 

 luscous order of prior arrangements. 



Many of these classes have inferior sections and subsections, under 

 which the genera that appertain to them are respectively marshalled. But 

 in a general outline it is not necessary to follow up the arrangement more 

 minutely. 



The common classification of zoological writers of the present day, is 

 still that of Linneus ; and as such, it is that which I shall regularly follow 

 up in the remainder of the present study, as being best adapted to popular 

 purposes. It is probable, however, that the classification of Cuvier will 

 ultimately take the lead of it ; it is somewhat more abstruse, but consi* 

 derably more definite ; and offers a noble specimen of scientific ingenuity, 

 apphed to one of the noblest branches of scientific study ; and I shall hence 

 advert to this classification as we proceed, for a comparison with that of 

 the justly celebrated Swedish naturalist. 



The Linndan system of zoology divides all animals into six classes, and 

 each class into a definite number of orders ; every order consisting of an 

 indefinite number of kinds of genera ; and every kind or genus of an in* 

 definite number of species : the individuals in each species being perhapg 

 innumerable. 



The six classes are as follows : I. mammals, or suckhng animals ; II. 

 birds ; III. amphibials ; IV. fishes ; V. insects ; VI. worms. 



These may be contemplated either in an ascending or a descending 

 scale. As we have begun with brute matter, and have progressively pur- 

 sued it from a shapeless mass to mineral crystallization ; from mineral 

 crystalHzation to vegetable organization, and from vegetable organization 

 to animal spontaneity ; it will be most congruous still to continue in the 

 same direction, and to commence with the lowest class constituting the 

 worm tribes. 



I. Worms, in the Linnean vocabulary, is a term of far more extensive 

 import than in its popular signification ; and the reason of this we shall 

 perceive as we proceed. They include all animals below the rank of in- 

 sects, and are classically characterized, as being mostly without distinct 

 head and without feet ; the most prominent organs being their tentacles or 

 feelers. The class is divided into five orders ; intestinal, molluscous, 

 testaceous, zoophytic, and infusory. 



The FIRST ORDER or INTESTINAL, with a few exceptions which are found 

 in the waters, consists of animals that are uniformly traced in the bowels oi 

 the earth, or of other animals ; whence, indeed, their ordinal name. They 

 are ordinarily characterized asbeing.simple, naked animals, without limbs. 

 I shall instance as examples of it, the ascaris, which is found so frequently 

 in the intestinal tube of mankind, in the species of maw or thread- worm, 

 and round- worm : the taenia, which comprises among many others the two 

 species of tape-worm and hydatid ; and the filaria or Guinea- worm, which 

 inhabits both the Indies, and is frequent in the morning dew ; at which time 

 it winds unperceived into the naked feet of slaves, or other menials, and 

 creates the most troublesome itchings, frequently accompanied with in- 

 flammation and fever. The only method of extracting it is to draw it oul 

 cautiously by means of a piece of silk tied round its head as it peeps £row 

 the inflamed surface ; for if, in consequence of too much straining, the 

 animal should break, the part remaining under the skin will still survive, 

 grow with redoubled vigour, and occasionally augment the local inflnm- 



