4() I'liOCKEIJJNGS OF TUE NATIONAL MUbKUM vol. 6a 



POLYGNATHUS FOLIUM, new species 



Plate 7, fig. 5 



Crest simple with parallel vein-like striations crossing the flattish 

 lateral areas. 



Occurrence. — Mississippian (Hardin sandstone) : Mount Pleasant^ 

 Tenn. 



Holotype.—QdX. No. 11012, U.S.N.M. 



POLYGNATHUS RHOMBOIDEUS, new species 



Plate 7, fig. 6 



Our figure sIioavs the upper side of plate illustrating rather regu- 

 larly rhombic outline and coarse longitudinally arranged tubercles 

 of the lateral areas with a row of similar tubercles on the posterior 

 third of the crest. 



Occurrence. — Mississippian (Hardin sandstone) : Mount Pleasant^ 

 Tenn. 



Holotype.—C2Lt. No. 11013, U.S.N.M. 



POLYGNATHUS GERMANUS, new species 

 Plate 7, figs. 11, 12 



Related to P. rhoTnboideus., but has a more regularly lanceolate 

 outline and lacks the tubercles on the crest. 



Occuri'ence. — Mississippian (Hardin sandstone) : Mount Pleasant* 

 Tenn. 



Holotype.—C2it. No. 10997, U.S.N.M. 



POLYGNATHUS GLABER. new species 



Plate 7, fig. 13 



A lanceolate species doubtless allied to P. peracutus Bryant front 

 the Genundewa limestone (Devonian) of New York, but differing 

 conspicuously from it in its smooth instead of coarsely tuberculated 

 surface. 



Occurrence. — Mississippian (Hardin sandstone) : Mount Pleasant^ 

 Tenn. 



Holotype.— Cat. No. 11004, U.S.N.M. 



POLYGNATHUS CONFLUENS. new species 



Plate 7, figs. 14, 15 



Tliis new species belongs to the typical (lanceolate) group but is: 

 readily distinguished by the confluence and somewhat concentric 



