4 
BRITISH BEETLES. 
the division are the EarthWorm, Leech, Tape Worm, 
and Liver Fluke. 
The Echinodermata, which are often placed before 
the Vermes in an ascending scale, may be defined as 
animals with a radiate arrangement, the rays being 
usually five in number ; they possess a skin bearing 
spicules and more or less hardened by calcareous 
deposits, a digestive canal, a nervous system, a true 
vascular system, and a curious system of canals called 
a “ water-vascular ” system, which has a locomotive 
and often a respiratory function ; the Star-fishes and 
Sea-urchins (Echini) are well-known examples. 
The Arthropoda have a segmented body with 
jointed appendages or limbs ; they possess a brain and 
a ventral nerve cord ; a complete alimentary canal is 
always present, and the organs of circulation, respira- 
tion and sense, although very variable, are more or less 
perfectly developed ; the division is usually regarded 
as containing four subdivisions, the Crustacea, Arach- 
nida, Myriapoda, and Insecta; a fifth is now added, 
the Protraclieata, containing the curious genus 
Peripatus, with which however we need not here 
trouble ourselves. 
The Crustacea are characterized by the possession 
of branchice or gills, by means of which they breathe ; 
they have two pairs of antennas, and numerous paired 
legs are present on the thorax and usually also on the 
abdomen; the body is covered by an integument, 
which is often very hard, and is chiefly composed, in 
this case, of carbonate of lime; wings are never 
present; the eyes are often situated on stalks, and 
this character is used in subdividing the section. The 
Crab, Lobster, Cray- fish, Prawn, Shrimp, and Wood- 
