OP ANIMALS. 49 



to rosaceous or radiated flowers. Their structure is various, 

 for some are as simple as the most simple polypus, and others 

 are much more complicated ; the mouth is central, furnished 

 with tentacula, leading into a stomach, often ramified, but 

 which has no other issue. There are for the purposes of ge- 

 neration, a number of oviform internal Tbuds in particular 

 cavities. 



37. The echinodermata are the radiated animals, the or- 

 ganization of which is the most complicate: the class contains 

 the stellated, the spheroidal and the cylindric forms. They 

 have an internal cavity in which distinct viscera float; their 

 intestine has vascular like prolongations ramified through the 

 body. Some have a distinct anus; the organs of respiration 

 are ramified aquiferous canals ; the organs of generation are 

 oviform masses of internal buds, which terminate either at 

 the mouth or at the anus ; they have muscles, and in the 

 greater number there are particular organs of locomotion, 

 consisting in numerous tentacula terminating in the form of a 

 cupping glass, called feet ; the skin is well organized, and 

 often solid ; some have even nervous filaments. 



38. The articulated animals constitute a division of the 

 animal kingdom in which the body is symmetrical, divided 

 externally in a certain number of rings or moveable segments, 

 and formed by the skin, more or less tough and sometimes 

 hard, except between the intervals of the rings in which it al- 

 ways retains its softness and flexibility. Their muscles are 

 connected with the, inside of the skin; their nerves are cords 

 with enlargements at intervals, situated beneath the intestinal 

 canal. This type however comprehends extremely varied or- 

 ganizations. Some are vermiform, without head and articu- 

 lated feet, and can only creep: these are the worms and the 

 annelides. 



39. The intestinal worms, or the helminthia, which bear 

 some general resemblance to the radiata, have the body com- 

 monly elongated, cylindrical or depressed, naked and soft; they 

 have no organ either of respiration or circulation. Their genera- 

 tion is internal, gemmiparous, and sexual, oviparous; they inha- 

 bit the bodies of other animals, and present otherwise very dif- 



