144 



HISTORICAL PALEONTOLOGY. 



&, 



Fig. 87. 



uphatodes, natural 



and enlarged, Devonian, Europe and America; 

 t, Spircrbis Arkonensis, of the natural size and 

 enlarged ; c, The same, with the tube twisted in 



:ction. Devonian, America. (Ori- 



in many specific forms (figs. 86 and 87) ; but almost all the 

 known examples are of small size, and are liable to escape a 



cursory examination. 



The Crustaceans of 

 the Devonian are prin- 

 cipally Eurypterids and 

 Trilobites. Some of the 

 former attain gigantic 

 dimensions, and the 

 quarrymen in the Scotch 

 Old Red give them the 

 name of " seraphim/' 

 from their singular 

 scale -like ornamenta- 

 tion. The Trilobites, 

 though still sufficiently 

 abundant in some local- 

 ities, have undergone a 

 yet further diminution 

 since the close of the 

 Upper Silurian. In both 

 America and Europe 

 quite a number of gen- 

 eric types have survived from the Silurian, but few or no new 

 ones make their appearance during this period in either the Old 



the reverse di: 

 ginal.) 



Fig. . a , prors la.rns, enarge, pper 

 Silurian, America ; c, Spirorbls spinulijcra, of the 

 natural size and enlarged, Devonian, Canada. (Af- 

 ter Hall and the Author.) 



Fig. 88. Devonian Trilobites ft, Phacops latifrons, Devonian of Britain, the Conti- 

 nent of Europe, and South America ; b, Homalonotns armatus, Europe ; c, Phacops 

 (Trimcrocephalns) la-vis, Europe; if, Head-shield of Phacops (fortloctea) ^nimilains, 

 Europe. (After Salter and Burmeister.) 



World or the New. The species, however, are distinct ; and the 



