148 



CLASS M YRIAPODA. CLASS A N N E L I D A. EARTH-WORMS, ETC. 



CLASS IX. M YRIAPODA. 



THESE Animals are immediately distinguished from the Annelids by the presence of jointed legs, of which the number is so great that 



they are commonly known as Centipedes or Millipedes. 



MYRIAPODS are divided into two Orders, viz., SCOLOPENDR* and CHI- 

 LOGNATHOUS. Of the former, Lithobius is a representative ; and of the 

 latter, Pdydesmus, Glomeris, and Julus (proper), are presented as examples. 

 The rings which envelope their body are horny and more or less hard ; 

 are imDncateu or slightly overlapping each other, and are either entire and 

 cylindrical, as in Julus, or consisting of two semicircular pieces united by 



Julus. 



membrane, and depressed, as in Scolopendra. The number of rings varies, 

 increasing with the age of the animal, but in the Scdapendra it ranges between 

 fifteen and twenty-one. Neither ring is furnished with more than a single 

 pair of stigmata, or orifices of air-vessels, and sometimes only, the alternate 

 rings are so furnished, as in Scdvpendra. The row of pores on either side 



Scolopendra. 



of the body are for the secretion and discharge of an acrid and fetid fluid, 

 which serves as a sort of defence. The rings exhibit scarcely any difference 

 between each other excepting the head or skull, which upon its upper 

 surface presents only a shield-like disc, supports the eyes and the antennae, 

 and overhanging the parts composing the mouth, which consists, according 

 to Savigny, of a broad upper lip, of a pair of mandibles, a lower lip formed 

 by the junction of a pair of primary, and another of secondary maxillae ; 

 hence the term Chilognathous, or lip-jawed Order, applied by Latreille to 

 the Juli and their congeners. 



ILLUSTRATIVE EXAMPLES. 



POLYDESMUS. Antenna? seven-jointed, filiform ; the second joint much 

 shorter than the third ; body very long, linear ; segments laterally com- 



pressed and margined ; legs numerous, each segment having two pairs ; 

 eyes obsolete. 



The species of this genus are numerous beneath stones. 



Type of the genus, and 



Illustration : Polydesmus camplanatus. 



LITHOBIUS. Antennae setaceous, composed of nearly conical joints the 

 two first joints the largest ; lips broadly cut in front ; upper edge toothed, 

 and the eyes bent; legs fifteen pair, the upper half of many of the iiup* 

 hid under the other. 



Type of the genus is L.forficatus ; the Scdapendra forficatus of Linnxus, 

 common in the gardens in summer. 



Illustration : Lithobius vulgaris. 



GLOMERIS. Body oval, oblong, cmstaceous, revolute, with a row of 

 small scales on each side, of eleven or twelve segments, the last the largest, 

 semicircular ; antennae enlarged at their tips. 



Type of the genus, G. avalis. Found in the Ocean. 



Illustration : Glomeris zonatis. 



JULUS. Body cylindrical, very long, spirally twisted, formed of a great 

 number of narrow rings, most of which are provided with two pair of legs ; 

 rings not keeled on the side. 



These insects do not, as might be expected from the number of their 

 legs, move with quickness ; their motion is rather to be compared to the 

 crawling of an earth-worm. When at rest, they generally lie on one side, 

 the body being contracted into a spiral form, with the head in the centre. 

 They are oviparous, and when they are first hatched their body is simple, 

 worm-like, without any legs ; in eighteen days they assume the shape of 

 their mothers, but at first their body is only formed of twenty-two rings 

 and twenty-six pair of legs ; on each successive change of skin the animal 

 gains several pair of legs, till the body is composed of fifty-five rings in the 

 males, and sixty-three rings in the females. The animal throws off the 

 skin, not only of the body but also of the whole head, and of the trachea 

 and digestive canals. They generally live in sandy places, and the smallest 

 of them amongst moss and under the bark of trees. There are only a few 

 species found in Europe ; the largest belong to America. 



Several of the species are phosphorescent, and are often taken for glow- 

 worms. 



Type of the genus, J. terrestris of Linnams. 



Illustration : Julus sabulosus. 



CLASS X. A N N E L I D A. EARTH-WORMS, ETC. 



ANNELIDS are the only Animals of the Invertebrate Series that have red blood. They are mostly cylindrical in form, as the Nereis, 

 Eunice, and Earth-worm, though some are found of an ovaloid shape, as the Sea-mouse. Their general covering consists of a 

 series of rings, or segments of soft tegument, varying in different genera from twenty to more than five hundred, connected by 

 thinner bands ; and all of them, except the Earth-worms, live in water. The Annelids form a small and singular Class of Animals. 



ANNELIDS are thus divided : Suctorial (Leeches) ; Terricdkws (Earth- 

 worms) ; Tubicctaus (Inhabitants of tubes) ; and Errantes (Wanderers). 



The Leech (Hirudo) is too well known to require description ; it was 

 formerly found in several parts of England, but is now rare. It is said that 

 four or five of the principal London importers of medicinal Leeches bring 

 over from the Continent of Europe the amazing numlier of 8,000,000 

 annually. These are chosen from their having sharp, simple teeth, which 

 consequently make a wound easily healed ; whereas the other leeches have 

 generally blunt, or serrated teeth. 



Leeches breed in streams ; live on animal substances ; are active during 

 the day, immoveable at night ; are affected greatly by clianges in the state 



Leech. 



of the atmosphere ; and can live for a long time without food, owing to the 

 slowness of their digestion. 



The Earth-warm (Lumbricus) is chiefly remarkable for its power of 



