30 DEVONIAN FAUNA. 



1. Harpes macrocephalus, Gold/. PL II, figs. 19 — 23. 



1839. Harpes macrocephalus, Goldf. Nov. Acta Acad. Cses. Leop. -Carol., 



vol. xix, pt. 1, p. 359, pi. xxxiii, fig. 2. 

 ? 1840. — speciosus, Munst. Beitr., pt. 3, p. 43, pi. v, fig. 19. 



1841. — macrocephalus, Phil. Pal. Foss., p. 127, pi. lv, fig. 246. 



1842. — — 1)' Arch, and de Vern. Geol. Trans., ser. 2, 



vol. vi, pt. 2, p. 337. 



1843. Goldf. Neues Jahrb. f. Min., Ac, 1843, p. 548. 

 1846. — ungula, Burmeister. (Not Sternberg.) Org. Trilobites, Eay Soc , 



p 75, pi. i, fig. 11. 

 1853. — macrocephalus, Steininger. Beschr. Geol. Eifel, p. 89. 

 1886. — — Barrois. Ann. Soc. Geol. du Nord., p. 175, 



pi. iv, fig. 3. 

 1888. — — Etheridge. Foss. Brit., vol. i, Pal., p. 145. 



Description. — Head-shield large, arch-shaped in outline ; margins nearly circular 

 in front, straight and slightly inclining to each other on the sides ; central portions 

 of the head spheroidal, surrounded by a perfectly flat marginal expansion occupying 

 about half its area. Latero-posterior angles of the cheek very long, acutely 

 angular, deflected laterally upwards from the marginal plane, and produced back- 

 wards beyond the centre of the body. Central portions of the head rising 

 suddenly and steeply, divided by a line at a distance equal to the width of the flat 

 marginal area; portions of cheek within this convex. Glabella elongate and 

 elevated, cylindrically oval, becoming indistinct beyond this first boundary-line, 

 but extending as far as the second ; narrowed in the posterior part ; with a small 

 sub-triangular lateral lobe separated by an indistinct oblique basal (?) furrow. 

 Neck-furrow deep. Neck-lobe short, narrow, and prominent, but much lower 

 than the front lobe. 



Eyes small, knob-like, close behind the anterior end of the glabella. 



Exterior surface smooth or very minutely tuberculate on the glabella and 

 cheeks within the first bounding line, which is defined by the surface beyond it 

 suddenly becoming punctate. Flat area coarsely punctate; the punctations 

 largest close to its inner boundary and to the border. 



Test thick, with several layers ; texture cellular, except at the border and in 

 the central region, where it is dense. Border with two or three strong sharp 

 ridges below. 



Tail very small, wide, triangular in outline ; apex blunt ; margin obliquely 

 flattened. Axis short, wide, convex, with five nodulous ribs ; limb flat centrally, 

 but bent suddenly downward near the border with a sharp angle, bearing four 

 bifurcating ribs reaching the border. 



