CRUSTACEANS. 233 



Calymene rugosa Shumard. 



Calymene rugosa Shumard, 1855: Geol. Sur. Missouri, Ann. Rep., p. 

 200, pi. B, lig. 14. 



Pygidium about two-thirds as long as wide ; posterior mar- 

 gins nearly straight, sharply rounded in the vicinity of the 

 median lobe. Axial lobe not quite one-third the lobal width of 

 the pygidium, composed of eight segments separated by sharp, 

 rather deep grooves. The lateral lobes have about five seg- 

 ments, each one having a shallow median lurrow which divides 

 it into two nearly equal parts. 



Horizon and localities. — Upper Cambrian ? limestone : Bir- 

 mingham ( Cape Girardeau). 



Ptychoparia conica? (Billings). 

 Bathyurus conicus Billings, 1859: Can. Geol., vol. IV, p. 336. 



Horizon and localities. — Cambrian, Magnesian limestone : 

 Hazelton ( Texas county ). 



Proetus mlssouriensis Shumard. 



Proetus missouriensis Shumard, 1855: Geol. Sur. Missouri, Ann. Rep., p, 



196, pi. B, figs. 13a-b. 

 Proetus auriculatus Hall, 1861 : Desc. New Species Foss., p. 79. 

 Proetus auriculaius Hall, 1862: New York State Cab. Nat. Hist., loth 



Rep., p. 107. 

 Phillipsia shumardi Herriclf, 1887 : Bui. Dennison Univ , vol. II, p. 58, pi. 



vii, fig. 14. 

 Proetus missouriensis Vogdes, 1887: Ann. New York Acad. Sci., vol. IV, 



p. 75, pi. iii, fig. 1. 

 Proetus missouriensis Hall, 1888: Pa). New York, vol. VII, p. 133, pi. 



xxiii, fig. 32. 



Much larger than P. swallovi. Glabella large, ovoid, 

 broadly rounded, and a little flattened in front, slightly broader 

 behind than before ; the posterior pair of furrows is more 

 strongly marked than the two other pairs. Pygidium semi-cir- 

 cular, somewhat flattened, with a broad marginal area. Axial 

 lobe occupying about one-third the breadth of the entire tail- 

 piece ; segments, 10 in number, with strongly defined furrows 

 separating them. Entire surface covered with small granules, 

 which are larger on the glabella than elsewhere. 

 G— 16 



