Mixopterus multispinosus (Clarke & Ruedemann) 



See plate i, figures 3-7; plate 3, figures 5, 6 



Fig. I Dorsal aspect of specimen retaining the preabdomen and 

 three segments of the postabdomen, as well as a fragment 

 of the second endognathite. Natural size, taken from mold 

 Fig. 2 Ventral view of same specimen 



Fig. 3 Dorsal view of abdomen, showing well the "dorsal furrows" 

 Fig. 4 Opercular appendage (of original of figure 2). x 3 



Originals from Vernon shale at Pittsford, N. Y., and now in the 

 New York State Museum. 



