508 Systematic Paleoxtology 



Subgenus CHASMOPS McCoy 



Dalmaxites (Chasmops) anchiops (Green) 

 Plate XCTII, Fig. :> 



Calymcne anchiops Green, 1832, Mon. of Trilobites of North America, p. 35. 

 Asaphus laticostatus Green, 1832, ibid., p. 45. 



Phacops anchiops Burmeister, 1846, Die Organisation der Trilobiten, p. 90. 

 Dalmania anchiops Hall, 1861, Description of New Species of Fossils, etc., 



p. 55. 

 Dalmania anchiops Hall, 1862, 15th Ann. Rept. N. Y. State Cab. Nat. Hist., 



p. 83. 

 Dalmanites anchiops Hall, 1876, Hlus. Devonian Fossils, pi. ix, figs. 1, 3-6, 10, 



12, 13; pi. X, figs. 6-14. 

 Dalmanites (.Chasmops) anchiops Hall and Clarke, 1888, Nat. Hist. N. Y., 



Pal., vol. Tii, p. 59, pi. ix, figs. 1-6, 10, 12, 13; pi. x, figs. 1-14. 



Description. — " General form and proportions. Body subelliptical in 

 outline, more or less produced at the extremities. Surface depressed con- 

 vex, distinctly trilobate; lateral margins deflected and subparallel. 

 Length (including caudal spine) to width as 2 to 1. Cephalon relatively 

 short, length about one-third the width ; outline crescentic, slightly pro- 

 duced on the frontal margin. Surface evenly convex. Border narrow 

 anteriorly, bearing in front of the glabella five to seven low crenulations 

 or undulations, which become wider and thicker upon the cheeks, and 

 produced at the genal angles into stout and rapidly tapering spines, which 

 reach the third thoracic segment. Doublure wide and deep at the genal 

 angles, narrowing at the lateral margins, and extending into a relatively 

 narrow epistoma in front. Facial sutures normal. 



" Glabella elongate, subpentagonal, widest anteriorly, depressed convex; 

 bounded on all sides by low sulci. Anterior lobe large, subrhomboidal ; 

 first pair of lateral furrows long, inclined backward; second pair obsolete, 

 except at their proximal extremities, where they appear upon the cast as 

 two deep pits ; third pair transverse or inclined slightly forward, almost 

 obsolete at their distal extremities; first and second glabellar lobes coa- 

 lescent, forming a single pair of large convex lobes, whose elevation ex- 

 ceeds that of the frontal lobe ; third glabellar lobes narrow, depressed and 

 relatively inconspicuous. Occipital furrow narrow on the axis, becoming 

 broader and deeper on the cheeks, occipital ring prominent and bearing 



