170 



ECHINODERMATA. 



the locomotive suckers are lost, and the only external resemblance left 

 between the now worm-like body and the forms above enumerated, is 

 met with in the radiating tentacula that 

 surround the mouth. The apodous Echino- Fig. 86. 



dermata (" Echinodermes sans pieds " of 

 Cuvier) have indeed been expunged from 

 the list of radiated animals by some modern 

 writers ; but in every point of their internal 

 structure we shall find them offer too 

 many points of similarity to permit of their 

 expulsion from the class under considera- 

 tion, although they evidently form the con- 

 necting link between the RADIATA and the 

 lowest families of the Annulose division of 

 the animal kingdom. The genus Fistularia 

 (fig. 86) strikingly exhibits an approxima- 

 tion to the outward form of the ANNELIDA ; 

 and the anatomy of these creatures, which 

 we shall afterwards consider, equally indi- 

 cates the affinities that unite them. 



(444.) We have already, when speaking 

 of the general division of the ECHINODEE- 

 MATA, put the reader in possession of all 

 that is satisfactorily known concerning the 

 structure of the Crinoid* genera, our 

 knowledge of those singular animals being 

 entirely derived from the exterior confor- 

 mation of a few recent species, and from 

 the mutilated skeletons of fossil Encrinites, 

 which exist in such abundance in the lime- 

 stone strata of our own country. 



(445.) Commencing, therefore, with the 

 ASTEEIDJE *}*, we shall now enter at once 

 upon the consideration of the anatomy of 

 such species as have been most carefully 

 examined, and merely notice incidentally 

 the modifications which occur in the dispo- 

 sition of various organs in kindred genera. 



(446.) On examining a living Asterias, 

 the outer covering of its body is found to be 

 composed of a dense coriaceous substance, Fistularia 



in which numerous calcareous pieces are 



apparently imbedded. The coriaceous integument is generally coloured 

 * Kpivov, a lily ; et^os, likeness, 

 t The name of this family and of its typical genus is derived from dffn'ip, a star. 



