May, 1919] Siluria^i Fossils From Ohio 401 



species evidently is closely similar to the Ohio forms here 

 described. The specimens described by Kindle from the 

 Niagaran at Pendleton, Connor's Mill, and Georgetown, 

 Indiana, usually lack all but the continuous posterior glabellar 

 furrow, although sometimes also the anterior and middle 

 glabellar furrows are present. Evidently all of these forms are 

 closely related. Apparently their derivation is from some of the 

 early species of Pterygometopus. 



A comparison of the Cedarville specimen, described above, 

 with Phacops stokesii Milne-Edwards, the type of the subgenus 

 Portlockia, indicates that the Cedarville specimen belongs to 

 the same subgenus. 



Dalmanites brevigladiolus, sp. nov. 

 Plate XVIII, Figs. 4 A-E. 



Pygidium terminating in a short but relatively very broad spine. 

 In a pygidium whose axial lobe originally must have equalled at least 

 18 mm., possibly 20 mm., the width of the pygidium at the posterior end 

 of the axial lobe equals 8 or 9 mm.; at 4 mm. from this axial lobe the 

 width of the terminal spine has narrowed to 6 mm.; at 7 mm. it has 

 narrowed to 4 mm. ; it terminates at 9 mm. with a very blunt curvature. 

 The axial lobe is rather low and depressed; it is crossed by 15 or 16 

 transverse rings of which the last three tend to be indistinct ; the trans- 

 verse grooves tend to be less distinctly defined along the median line. 

 Pleural lobes with at least 6 or 7, sometimes possibly 8 ribs, all of which 

 are marked by a median groove. In some specimens the more posterior 

 grooves start off near the posterior margin of the rib and become median 

 at mid-length. For a width of slightly more than a millimeter the 

 lateral margins of the pygidium tend to be smooth, unmarked by the 

 terminations of the pleural ribs. There is a tendency toward extremely 

 low, practically obsolete tuberculation along the axial lobe. 



In the only full sized specimen of a cranidium known the glabellar 

 furrows are distinctly defined. The anterior margin of the cranidium 

 has a flat, rounded, median lip-like extension, about the same size as in 

 Dalmanites platycaudatus, Weller (Bull. Chicago Acad. Sci., Nat. Hist. 

 Surv., No. 4, pt. 2, 1907, p. 272, pi. 25, figs. 3-5), with which the species 

 evidently is closely related, differing chiefly in the shorter length of the 

 flattened caudal spine. 



Position and Locality: In the Holophragma zone, at the 

 top of the Lilley member of the West Union formation, in the 

 Zink or Corporation quarry, in the eastern part of Hillsboro, 

 Ohio. 



