218 rAL.EONTOLOGY. 



CREPICEPHALUS (LoGANELLUS) SIMULATOU 11. Sp, 

 Plate II, ligs. lC-18. 



Head within the fociul sutures quadrangadar in form, exclusive of the 

 postero-lateral limbs, slightly contracted in width in the region of the eyes. 



( ilalxdla narrowly conical, very gradually tapering from the base ante- 

 riorly, the sides nearly straight, and rather squarely truncate in front; 

 l)(ird('r(*d l)y distinct, impressed, dorsal furrows; surface evenly convex 

 throughout, and marked by three pairs of faint, moderately oblique, trans- 

 verse furrows; the two anterior ])airs not extending- quite one-third of the 

 width of the glabellii; third or jxisterior pair longer, but faintly marked, 

 tlicir inner ends strongly recurved,"almnst separating the ])osterior glabellar 

 lobes; occi[)ital furrow distinct; ring prominent and rounded. 



Fixed cheeks of moderates width, prominent at the eye-lobes, and 

 nipidlv declining in front and behind; ocular ridges faintly marked. 

 ]""n>ntal Tunlj longer than the width of the fixed cheeks, l)ordered by a nar- 

 row, elevated lim, between which and the front of the glabella it is distinctly 

 convex, and the part inniiediately in front of the glabella more strongly 

 convex. lM(^-lobes small. Posterior lateral limbs not known. Surface of 

 crust smooth. 



Specimens of moval)lc cheeks associateil with the n1)ove, and corre- 

 sponding in cliaracter, are somewhat triangular in form; margiiieil l)y a 

 slightl} -llaltened, elevated border of moderate Avidth, which is continued 

 in a long, rather slender s])ine a.t the posterior angle; iinier area of the 

 cheek convex and distinctly marked with radiating stri;e; inner angle 

 strongly notched for the proportionally large eye-lobe. Pygidium un- 

 kmiwn. 



The species very closely resembles in form and characters the corre- 

 sponding parts of C. (L.) macidosus, but is somewdiat shorter in proportion 

 to the Avidth; the glabella is not rounded at the summit as in that sjiecies, 

 and the furroAvs are more distinctly marked and not so obli<|ue, Avhile the 

 surface does not possess the pustules characteristic of that one. 



Formation and local itij.—^n limestone of the Potsdam group, at Eureka, 

 Nevada. Collected by Arnold Hague, esq. 



