DISTINCTIVE CHARACTERS OF ANIMALS. 



175 



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

 ceive as we proceed. They include all animals below the rank of insects, 

 and are classically characterized, as being' mostly without distinct head and 

 without feet ; the most prominent organ 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 of 

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

 are ordinarily characterized as being 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 spe- 

 cies 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 cre- 

 ates the most troublesome itchings, frequently accompanied with inflammation 

 and fever. The only method of extracting it is to draw it out cautiously by 

 means of a piece of silk tied round its head as it peeps from the inflamed sur- 

 face ; 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 inflammation to such an extent, 

 as to prove fatal. It is often twelve feet long, though not larger in diameter 

 than a horse-hair. 



The next intestinal worm at which it is worth while to throw a glance as 

 we pass on, is the fasciola or fluke, principally known from one of its spe- 

 cies being found in large abundance in the liver of sheep during the disease 

 called the rot, but whether the cause or the result of this disease has never 

 yet been sufficiently ascertained. There are other species of this animal 

 found in the stomach, intestines, or liver of various other animals, and occa- 

 sionally of man himself. The fasciola is hermaphrodite and oviparous. 



The gordius or hair-worm is chiefly worthy of notice as being supposed, in 

 one of its species, if incautiously handled, to inflict a bite at the end of the 

 fingers, and produce the complaint called a whitlow. It inhabits soft stagnant 

 waters, is from four to six inches long, and is almost perpetually twisting 

 itself into various contortions and knots. 



The last two kinds I shall enumerate under this order of worms are, the 

 lumbricus or earth-worm, including the dew-worm and the slug ; and the 

 hirudo or leech, both of them too well known under several species to require 

 any farther remark in the present rapid outline. This order includes nearly 

 the whole of M. Cuvier's class of worms, with the exception of his sea-worms, 

 already adverted to. 



The SECOND ORDER of the WORM CLASS is denominated mollusca, molluscous, 

 or soFT-BODiED SHELL-WORMS ; and consists, for the most part, of similar 

 animals to those found in snail, oyster, nautilus, and other shells, but without 

 a shelly defence : and hence, in their ordinal character, they are described as 

 simple animals, naked, but furnished with limbs, of some kind or other. By 

 this last mark they are distinguished from the preceding, or intestinal order, 

 which, as already observed, consists of simple animals, naked and destitute 

 of limbs. To place the order more immediately before you, I shall select a 

 few examples from those animals that are most familiar to us, or are most 

 remarkable for the singularity of their structure or other properties. 



The limax or slug is one of the most simple animals that belong to this 

 order : its only limbs are four feelers, tentacles, or horns, as they are com- 

 monly called, situate above the mouth, with a black dot at the tip of each of 

 the larger ones, which is supposed to be an eye, though this point has not 

 been fully established. Another genus of molluscous worms is the terrabella ; 

 one species of which is the ship- worm, with an oblong, creeping, naked body, 

 and numerous capillary feelers about the mouth, from four to six inches in 

 length. It is sometimes enclosed in a testaceous or shelly tube, and is then 



