THE SUB-KIXGDOIIS. I07 



series of segments placed one behind the other, nor are 

 their limbs disposed symmetrically on the two sides of 

 the animal. Examples of the sub-kingdom are the Star- 

 fishes, Sea-urchins, Tape-worms, Round-worms, ^\ heel- 

 animalcules. &c. 



STJB-KINGDOM IV. ANNULOSA. 



The name Anmdosa is derived from the fact that the 

 animals included in this sub-kingdom possess bodies 

 ^N-hich are composed of a succession of distinct segments 

 or "rin-s" (Latin, anmdus, a ring). The sub-kingdom 

 includes the classes of the Annelida, Crustacea, Arachnida, 

 Myriapoda, and Inseda, which agree with one another m 

 the following characters -.-The body is composed of suc- 

 cessive rings or segments placed one behind the other m 

 a longitudfnal series. The body-cavity never communi- 

 cates with the exterior through the mouth. There is 

 mostly a well-developed digestive system, which is always 

 shut off from the body-cavity. The nervous system con- 

 sists of a double chain of little nervous masses placed 

 aloncr the "ventral" or lower surface of the body and 

 united by longitudinal cords. The limbs (when present) 

 are turned towards that side of the body upon which the 

 nervous system is situated, and they are mostly arranged 

 in symmetrical pairs on the two sides of the body. Ex- 

 amples of the sub-kingdom are the Leeches, Earth-worms, 

 and Sea-worms; the Lobsters, Shrimps, and Crabs ; the 

 Spiders and Scorpions; the Centipedes and Milhpedes ; 

 and the true insects (Beetles, Butterflies, Dragon-flies, 

 House-flies, and the like). 



SUB-KINGDOM V. JIOLLUSCA. 



The name of this sub-kingdom is derived from the fact 

 that the animals comprised in it have soft bodies (Latin, 

 mollis, soft) ; and they are commonly called ^l^eU-lisb 

 because the soft body is generally protected by a hard 



