A Contribution to the Lower Devonian Faunas of Maryland 57 



ing the marginal denticles, being finely papillose. Thorax consisting of 

 eleven segments, the axis a little less than one-third the entire width, 

 pleurre extended into sharp, posteriorly pointing spines. Pygidium siib- 

 triangular in outline, the posterior extremity produced into a dorsally 

 curving, attenuate spine, a little less than one-fourth the total pygidial 

 length. Axis depressed convex, indistinctly subangular along its median 

 line, about one-fourth the entire width of the pygidium at its anterior 

 margin, its sides nearly straight, gradually converging to the obtusely 

 rounded posterior extremity, which lies a little anterior to the base of the 

 posterior pygidial spine. Pleurae with no conspicuous marginal border, 

 flattened above, l)ecoming rather strongly convex in the middlp, and then 

 sloping away to the lateral margins with a slightly convex surface. Axial 

 segments fifteen in number; pleural segments grooved, eleven in number, 

 curving rather abruptly backward as they approach the margin, the two 

 or three posterior ones nearly straight. Each segment of the pygidium 

 marked by a more or less irregular line of tubercles." Weller, 1903. 



The pygidium figured has a striking resemblance to published figures 

 and descriptions of this species in the duplicate ribs and in the tubercles 

 on the axial lobe. But except for the width of the axis, it might with equal 

 propriety be referred to Z>. Usignatus Clarke. It is too imperfect for 

 accurate determination. 



Occurrence. — Oriskany Formation, Eidgely Member. Evick Gap, 

 opposite Franklin, Pendleton County, West A^irginia. 



Collection. — U. S. National Museum. 



Dalmanites micrurus (Green) 

 Plate XCI, Figs. 10, 11 



Asaphus micrurus Green, 1832, Mon. Trilobites of North America, p. 56, cast 



19, fig. 3. 

 Dalmania micrurus Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 359, pi. Ixxiv, 



figs. 13-20, 1861. 



Description. — Hall describes this species as follows : " Pygidium tri- 

 angular, convex, somewhat abruptly sloping at the sides, acute, attenuate 

 behind. Axis very prominent, faintly subangular in the middle above, 

 and regularly rounded towards the posterior extremity, rigid, scarcely 

 declining below, and abruptly elevated from the posterior marginal 



