20 INTRODUCTION TO ZOOLOGY. 



instantaneous flash a peculiarity alluded to by Crabbe, with 



his usual minute accuracy: 



" See, as they float along, th' entangled weeds 

 Slowly approach upborne on bladdery beads ; 

 Wait till they land, and you shall then behold 

 The fiery sparks those tangled fronds unfold 

 Myriads of living points; th' unaided eye 

 Can but the fire, and not the form, descry." 



ORDER II. ASTEROIDA. 



" We'll dive where the gardens of coral lie darkling, 

 And plant all the rosiest stems at thy head." MOORE. 



THE animals of the present order are all marine. They are 

 never found singly, but in a com- 

 munity, forming altogether a polype- 

 mass, variable in form, strengthened 

 in different ways, and having on its 

 surface the cells in which the polypes 

 live, and which open on the surface 

 in a star-like figure, whence the order 

 takes its name (Fig. 10). 



To this order belong the family of 

 Pennatulida?, or Sea-pens. One 

 species, taken in abundance on some 

 parts of the Irish coast, is the Vir- 

 gularia mirdbilis, a name which 

 denotes the beauty and singularity of 

 its appearance, for it literally means 

 ' ' wonderful little rod. " It is dredged 

 from a muddy bottom, in water a 

 few fathoms deep, and comes up so 

 perfectly clean, that fishermen sup- 

 pose it stands erect at the bottom, 

 with one extremity fixed in the mud. 

 From the summit to the base of the 

 Virgularia runs a long white, cal- 

 careous substance an axis uniform 

 in thickness throughout. This is the 

 first instance which has as yet come 



before us of an animal possessing 



Fig. 10. ASTEROID POLYPES, the power of secreting calcareous 



matter; a power so remarkably developed in those polypes 



