DISTINCTIVE CHARACTERS OF ANIMALS. 



mation 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 

 species 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 ani- 

 mals, and occasionally 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 two last 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 outhne. This order in- 

 cludes nearly the whole of M. Cuvier's class of worms, with the exception 

 of sea-worms, already adverted to. 



The SECOND ORDER of the WORM CLASS is denominated mollusca, mol- 

 luscous, 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 belongs 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 

 terebella ; 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 called termes, pipe- worm, or shelly ship-worm, and be- 

 longs to the next order. In both forms it is peculiarly destructive to ship- 

 ping ; boring its way into the stoutest oak planks with great rapidity and 

 facility ; and chiefly forming a necessity for their being copper bottomed. 

 The animal is, in its habits, gregarious ; and hence, in attacking a vessel, 

 it advances in a multitudinous body, every individual punctiliously adhering 

 to its own cell, which is separated from the adjoining by a partition not 

 thicker than a piece of writing-paper. In a preceding lecture, however, I 

 had occasion to observe, when glancing at the shelly ship-worm, or teredo 

 navalis^ that by its attacking the stagnant trunks of trees and other vegeta- 

 ble materials, that in many parts of the world are washed or thrown down 

 by torrents and tornadoes from the mountains, and block up the mouths 

 *>f creeks and rivers, and thus powerfully contributing to the dissolution of 



I 



