NORTONECHINUS, A DEVONIAN ECHINOID. 221 
EXPLANATION OF PLATE. 
Nortonechinus primus n. sp. 
Figs. 1-2.—Obverse and reverse of a plate. x 2. 
3-4—Distal and lateral views of a typical spine. x 2. 
5.—Drawing to illustrate the attachment of spine to plate. x 2. 
6.—Mass of plates and spines. The spines probably are those 
of the periphery. x 1. 
7-8.—Distal and lateral vie ws of another type of spine, which is 
marked by vertical striae. x 4. 
