Pterygotus ? vernonensis nov. 

 Fig. I Carapace, natural size • 

 Fig. 2 Carapace (type specimen) x 3 



Mixopterus multispinosus (Clarke & Ruedemann) 



See plate 2, figures 1-4; plate 3, figures 5, 6 



Fig. 3 Dorsal view of most complete specimen found, seen from the 

 interior. Natural size 

 a Anterior lobe of marginal shield of ventral integument 

 h Antero-lateral lobe of carapace 

 c Second endognathite 

 d Clasping organ in place 

 Fig. 4 Diagram showing relative position of lobes of dorsal {h) and 

 ventral sides (a) of carapace. The portion of the cara- 

 pace exposed on dorsal side is shaded 

 Fig. 5 Telson spine. Natural size 

 Figs. 6, 7 Metastomas. Natural size 



The originals are from the Vernon shale at Pittsford, N. Y., and 

 are in the New York State Museum. 



3l8 



