May, 1919] Silurian Fossils From Ohio 399 



In the variety rogersensis, these larger granules occur also in moderate 

 numbers on the other glabellar lobes, on the neck ring, and less promi- 

 nently, even on the fixed cheeks. This may be due chiefly to their 

 larger size. The movable cheeks are smooth macroscopically. The 

 exceedingly minute granules, visible only under a magnifier, covering 

 the entire surface of the cephalon, appear more distinct in some speci- 

 mens of carleyi than in any known specimens of rogersensis. In Dal- 

 manites carleyi (Plate XIX, Fig. 17), a spinose granule ornaments 

 the middle of the neck ring, close to the posterior margin. The presence 

 of this spinose granule has not been demonstrated in any specimen of 

 the variety rogersensis, but this part of the neck ring is defective in all 

 specimens of rogersensis found so far. 



The type of Dalmanites carleyi-rogersensis was obtained 

 north of Rogers Gap, at a point 54.8 miles from Ludlow accord- 

 ing to the mile posts along the railroad. Here it occurred in 

 the Rogers Gap division of the Cynthiana formation. A figure 

 of the type specimen under the name of Dalmanites achates, was 

 presented in the Journal of the Cincinnati Society of Natural 

 History,' cited above, and an enlarged figure of the same speci- 

 men is provided here. (Plate XIX, Fig. 18 A). 



The posterior extremity of the pygidium of Dalmanites 

 carleyi is described as being curved a little upward. This 

 feature is shown also by a specimen of this species in my pos- 

 session. In a pygidium belonging to the variety rogersensis, 

 found north of Rogers Gap, this upward curvature of the 

 posterior extremity also is noted, while in another specimen 

 referred to the same variety, but found east of Hatton, in 

 Shelby county, Kentucky, the curvature of the posterior 

 extremity is distinctly downward. Apparently this can not be 

 recognized as a constant distinguishing characteristic. In the 

 Fairmount specimens of the species Dalmanites carleyi the ribs 

 on the pleural lobes of the pygidium are curved more or less 

 backward toward their extremities, especially in case of the 

 more posterior ribs. In the pygidia of the variety rogersensis, 

 so far known, these ribs are nearly straight. 



Phacops (Portlockia) mancus, sp. nov. 

 Plate XVIII, Fig. 3. 



Anterior part of glabella apparently forming the anterior part of the 

 cephalon; at least no trace of a border is noticed anterior to the glabella 

 except near the lateral margin of the latter; the outline of this anterior 

 part is semicircular. The dorsal furrows limiting the sides of the 

 glabella are distinct, especially where limiting the anterior part of the 



