II 



LIFE IN Tini EARLY CAMBRIAISI 



T N the old Chcildcan fable of the descent of Ish- 

 tar into Hades, to recover her lost Tammuz, 

 at each successive ^^ite of the lower rej^ions she 

 is stripped of some of her ornaments and garments, 

 till at length she has to appear naked and una- 

 dorned in the presence of the lord of the Nether 

 World. So in our descent from the surface on 

 which men live, through the successive rocky layers 

 of the earth's crust, we leave behind, one by one, 

 all the higher forms of life with which we are 

 familiar ; but there still remain to us our six groups 

 of aquatic invertebrates, in the guise, it is true, 

 of species and genera now unknown in a living 

 state, yet well represented as far down as the lower 

 part of the Cambrian. Let us now su}jposc that 

 we take our stand on the shores of the Cambrian 

 sea, or cast our dredge into its waters in search of 



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