is to say, it belongs with the spiders, its present- 

 day descendant being Limulus, the horseshoe-crab. 

 The horseshoe-crab, it should be pointed out, has 

 a peculiar embryology and development, very un- 

 like that of a true crustacean; and for that reason 

 its relationship with any living group is a proble- 

 matical one at best. Its ancestors, too, were among 

 the earliest inhabitants of this earth to bequeath to 

 posterity the first fossiliferous evidence of un- 

 doubted animal types. 



There is one group, or phylum, of marine ani- 

 mals, however, of which since the time of its most 

 ancient day no record has been traced. It was 

 ancestral to no land form, living or extinct. The 

 echinoderms, to which our serpent-star belongs, 

 have not now, and never have had, any relatives 

 near or remote living away from the sea. In this 

 isolation they are unique. Nature seems somehow 

 long ago to have abandoned all effort to lift them 

 to a higher plane; the modern representatives 

 appear not to be greatly altered in form during 

 these millions of years since their ancestors turned 

 to stone. 



That they have changed since those days, is 

 inevitable; but they have nowhere given rise 



[86] 



