Hughmilleria phelpsae nov. 

 Fig. I Specimen (cotype) retaining part of carapace, two tergites 

 and operculum with opercular appendage. Natural size 

 Fig. 2 Type of species, consisting of carapace and two tergites. 



Fig. 3 Enlargement (lo x) of sculpture of tergite 



Mixopterus multispinosus (Clarke & Ruedemann) 



See plate i, figures 3-7: plate 2, figures 1-4 



Fig. 4 Postabdominal segment. Natural size 



Fig. 5 Endognathite. Natural size 



Fig. 6 Nearly complete swimming leg. Natural size 



Hex£.meroceras chadwicki nov. 

 Figs. 7, 8 Two views of type specimen. Natural size 

 Fig. 9 Lateral view of cotype, showing length of living chamber and 

 depth of air-chambers. Natural size 

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

 and are now in the New York State Museum. 



