PLATE IX 

 TRIARTHRUS (Pages 213-219) 



Figure 1. — Triarlhrus Becki Green ; dorsal view ; showing character 

 and extent of antennules and limbs beyond the carapace. X 2-|. 



Figure 2. — Triarlhrus Becki Green; ventral view; showing entire 

 series of appendages, together with hypostoma, metastoma, and anal 

 opening. X 2^. 



Utioa Slate, Ordovician, near Rome, New York. 



