66 



THE CHAIN OF LIFE. 



l)eginning of the Siluro-Cambrian, continues to this day. Spirifcr 

 and Productus (Figs. 59 and 60) appear later, and die out at 



Kk;. 55^». — Tereliratuta saccnlus 

 (Mariin). Carboniferous. 



Fig. 56. - nischia Acndkn (Hartt). Lo >ver 

 Cainbru-ia of New liruiiswick. 



the close of the Palaeozoic. So strange and inscrutable arc 

 the fortunes of these animals, which on the whole have lost in 



Fig. 57. — Brachiopods; genus (?r//«i-. 



a O Billinesi (Hartt). Lower Cambrian, b, O. pectinella (Hall). Lower Silurian. 

 ,u V. muingsi yyxx^) ^^ ^ ^^^^^ (Eichwald). Lower Silurian. 



the battle of life, so that their place in nature is vastly less 

 important than it was. it has been suggested that if any group 



.^^l^ 



J\ : ML Ji t i/ 



wmBWBfl^ 



Fig i^.—Rhynchonelia tncreoresccns (Hall). Lower Silurian. 



of c-eacures could thr-^w light upon the theory of descent with 

 modification, it would be these ; but Davidson, who has perhaps 



