CONTRIBUTIONS TO PALEONTOLOGY. 153 



CONOCEPHALITES PERSEUS (n. s.). 



PLATE VII, FIGS. 17-23; AND PLATE VIII, FIG. 33. 



Glabella cylindrico-conical, gibbous, rounded at the anterior ex- 

 tremity. Glabellar furrows very distinct; the posterior furrows 

 oblique and deeply impressed, and extending across the gla- 

 bella : the second furrows are nearly rectangular to the axis, 

 distinct at the sides, and extending almost across the glabella; 

 anterior furrows obscure or obsolete, and close to the anterior 

 extremity, the anterior* lobe very short. Occipital furrow com- 

 paratively deep, curving forward in the middle and at the 

 extremities : occipital ring as high as the posterior part of the 

 glabella, or sometimes a little higher. Dorsal furrow sharply 

 an<l ricatly defined, and its continuation in front almost as well 

 marked as at the sides. 



Facial suture vertical in its anterior line, curving at the promi- 

 nent palpebral lobe, and making a sharp curve outwards at its 

 lower angle. 



Fixed cheeks narrow; palpebral lobe prominent ; posterior limb 

 narrow triangular ; frontal limb short and traversed in the 

 middle by a deep groove, from which the narrow anterior mar- 

 gin rises abruptly : outline in front a little produced in the 

 middle. The centre of the palpebral lobe is opposite the middle 

 of the glabella. In the very gibbous form of the glabella and 

 deeply marked posterior furrows, which are united across the 

 middle, and in the narrow and deeply grooved frontal limb, it 

 differs from any of the species described. 



A pygidium associated with numerous specimens of the glabella 

 is nearly semicircular, slightly curved on the anterior margin, 

 with a narrow prominent axis which is marked by three or four 

 annulations besides the terminal one, the latter bearing two ob- 

 scure nodes. The lateral lobes are scarcely convex, with about 

 three divided ribs. 



This species occurs on the Mississippi river, opposite the mouth of the 

 Chippewa, associated with Conocephalites diadematus and Arionellus hi' 

 punctaius. It likewise occurs in gray ferruginous sandstone at Kickapoo, 

 associated with C. shumardi; differing from that one conspicuously in its 

 more cylindrical glabella. 



[Senate, No. 115.] 20 



