156 PALEONTOLOGY OF OHIO. 



an extent as to preclude the possibility of a specific identification, while 

 there are none represented on the segments of the lateral lobes. 



Formation and locality: In limestones of the Niagara group, at Eaton and Yellow 

 Springs, Ohio. Collected, by Prof. Edward Orton. 



Genus LICHAS, Dalman. 

 LiCHAS BREVICEPS. 



Plate 7, fig. 17. 

 Lichas breviceps, Hall ; Trans, Alb- Inst., Vol. IV., p. 222, 1862. 



Among the remains of trilobites from the Niagara group there is a 

 single imperfect glabella and a portion of a pygidium which appears to 

 belong to the above named species. The glabella has been very short 

 and broad, and very distinctly divided into three lobes, the central one 

 being broad and rounded in front, and abruptly contracted j^osteriorly, 

 but again slightly expanding just in front of the occipital furrow. The 

 lateral lobes are proportionally large, sub-reniform, as long again as wide, 

 and a little wider than the narrowest part of the central lobe, placed 

 with their rounded or convex sides against the central lobe. The front 

 of the head is broadly rounded, and bordered by a very narrow, thick- 

 ened, cord-like, closely appressed rim. Occipital ring broad and flattened. 

 Surface very finely pustulose, appearing to the unassisted e3'e only as 

 finely granulose, E3^es and movable cheeks not observed. 



The pygidium associated with the glabella is semi-oval, longer than 

 wide — the axis at its anterior end forming a little more than one- third 

 of the entire width, the form being elongate tringular, marked by only 

 two distinct rings, the furrows between them not extending entirely 

 across the lobe, and the posterior extremity of the lobe bluntly rounded. 

 Lateral lobes flattened, marked by three pairs of furrows ; but the speci- 

 men is too imperfect to show whether there has been more than one 

 point on each side above the central or terminal one ; but the evidence, 

 as furnished by the direction of the furrows and striae on the under sur- 

 face, would indicate the existence of two points. 



The original specimen of L. breviceps is from the Niagara group, at Wal- 

 dron, Indiana, and although, on comparison, there are some slight differ- 

 ences noticed between them, they are not of sufiicient importance to be 

 considered of specific value. The species differs from L. Boltoni, of the 

 same formation in New York, in the shortness of the head, the greater 

 posterior breadth of the central lobe of the glabella, in the rounded front 



