744 THE PALEONTOLOGY OF MINNESOTA. 



[Odontopleuru parvula. 



Family ACIDASPID^E. 

 Genus ODONTOPLEURA, Emmrich, 1849. 

 OPONTOPLEURA PARVULA Walcott (sp.), 1877. 



Acidaspis parvula WALCOTT, 1877. Adv. sheets, Thirty-flrst Kept., N. Y. State Mus. Nat. Hist., 



p. 16. 



Acidaspis parvula WALCOTT, 1879. Thirty-flrst Bept., N. Y. State Mus. Nat. Hist., p. 69. 

 Odontopleura parvula CLARKE, 1892. Forty-fourth Kept., N. Y. State Mus., p. 101. 



The few fragments of this species which have been observed in the Minnesota 

 formations present no differences from the New York form. As the species is 

 frequently preserved in an entire condition in the Trenton limestone of Trenton 

 Falls, N. Y., a figure of such a specimen is here introduced. 



Fig. 61. Odontopleura parvula Walcott. x 3. Trenton Falls, N. Y. 

 Formation and locality. Galena, shales, St. Paul, Minnesota. 



Family LICHAD^E. 



Genus LICHAS, Dalman, 1826. 



Subgenus ARGES, Goldfuss, 1839. 



ARGES WESENBERGENSIS Schmidt, var. PAULIANUS, n. var. 



Cephalon convex, subsemicircular in anterior outline, projecting medially; 

 lateral extensions not exsert. 



Glabella regularly convex, anterior and lateral slopes the more abrupt. Median 

 lobe broadest on the anterior margin where it covers three-fourths of the entire 

 width of the glabella, regularly rounded, most convex just in front of its center. 

 Anterior and posterior glabellar furrows continuous and deep, setting off a pair 

 of simple, rounded, subovoid lateral lobes, bounded on the outside by the dorsal 

 furrows which are somewhat shallower than the inner furrows. The first and second 

 lobes are thus wholly coalesced, the third or occipital lobes being represented by a 

 pair of elongated nodes which at their union with the narrow posterior portion of 

 the median lobe form an obscure annulation. Occipital furrow broad; occipital ring 

 narrow, elevated on the axis and aspinous. The fixed cheeks and eye-node are 

 convex, the latter appressed to the glabella and somewhat posterior in position. 



