120 THE CLASSIFICATION OF CUVIER. 



is divided by transverse folds into a certain number of rings, 

 (th, b to 6 1 )." 



In his fourth grand division, Zoophyta, or Radiates, as he 

 frequently calls them, in which he includes not only starfishes, 

 sea-urchins, jelly-fishes, and corals, but also intestinal worms, and 

 infusoria, "the organs are arranged like rays around a centre," 

 or, as he expresses it in one place, (vol. in. p. 218, ed. 1829-30,) 

 u along two or more lines going from one pole to the other 

 (% 54)." 



rt~ 



BHBBI^ifiiaUUjritiiA3ka;^ 

 g h 1 g'* ayi 



Fig. 54. 



As a general thing, naturalists have accepted the divisions of 

 Cuvier; but there is a diversity of opinion in regard to the limits 

 of these divisions. Some accept them in the same sense as 



the heart ; .sg, superior nerve ganglion of head ; g, g*, ganglions of the thorax ; c, 

 nervous collar ; n, main abdominal nerve ; <7 2 , </ 3 , g 4 , ganglions of n ; ov, ovary ; 

 rf, oviduct ; o, exterior aperture of d. From Newport. Slightly altered. 



Fig. 54. Caudina arenata. Strap. Natural size. A longitudinal, semi- 

 diagramic view of a common Trepang of our coast, t, fl, the four-pronged, 

 anchor-shaped feelers of the head; f,f l , the stave-like, calcareous, forked pieces 

 of the buccal ring; 17, the anterior end of the intestine; gl, the first bend of the 

 same ; <? 2 , the second bend of the same ; $r 3 , the posterior or cloacal region of 

 the intestine ; </ 4 , posterior aperture of the same ; r<, r? 1 , rt 2 , the respiratory 

 branches ; m, the madreporic body ; me, the madreporic canal ; r, the aquiferous 

 ring; aq, the aquiferous canals going from r to the space (a<? 3 ) at the base of 



