68 G. F. MATTHEW: ILLUSTRATIONS OF 



Glabella large, eousisting of two lobes ; the anterior, semicircular, wider thau the 

 posterior lobe, elevated above the general contour of the surface, and, in some examples 

 uudiilate with broad furrows, spreading from the back of the lobe ; posterior lobe flattened, 

 cylindrical, with a broad, faint, median, transverse furrow, interrupted at the summit of 

 the glabella by a tubercle, elongated on the line of the axis. The cheeks are narrowed in 

 the middle, there being a crescent-shaped limb in front of the anterior lobe of the glabella, 

 and an expanded limb on each side of the posterior lobe of the glabella. 



Thorax, consisting of two (?) segments ; the anterior subarcuate, and marked by five 

 lobes that are bounded by furrows, radiating from the anterior curved margin ; the inner 

 pair of lobes are larger than the others. The posterior segment of the thorax is unknown. 



The pygidium is elliptical, with straight sides and truncated in front of the side 

 lobes ; it is widest at the anterior angles. The axial lobe is large, high, obtusely clavate, 

 constricted in the middle and divided into three lobes ; the middle lobe is larger than the 

 combined length of the anterior and posterior lobes, and bears an elongated ridge-like 

 tubercle on the axial line ; the bounding furrows are arched outward on the axial line, 

 thus encroaching upon the other lobes ; it is indented in the middle of its length on each 

 side by a short deep fvirrow ; the furrow at the back of this lobe is not constant in its 

 direction, and is sometimes faint or invisible near the axial line ; the anterior lobe is 

 narrow and ring-like, the posterior is sublunate. The lateral lobes of the pygidium are 

 narrowed opposite the posterior part of the axial lobe and more decidedly at the extremity 

 of the pygidial shield. 



This little species is remarkable for the large size of the glabella, and of the rachis of 

 the pygidium ; in these features and in the expanded anterior end of the glabella it resem- 

 bles A. rex (Barr.) and A. regius (Sjogr), but there are no raised lobes on the cheeks, and the 

 proportions of the glabella, etc., in our species differ from those of the two species cited 



Length, 6 mm. Width, 2| mm. 



Horizon and Loralily. Found in the fine, dark grey shales of Div. l.c, at Portland, and 

 at Hanford Brook and Porter's Brook, St. Martin's, but it is not common. 



Agnostus partitus, n. sp. (Plate YII. Figs. 2a. and b.) 



Elongate-elliptical, broader (and subquadrate ?) behind. 



Cephalic shield, elongate semi-elliptical, augulated at the posterior end. Dorsal furrow 

 distinctly impressed. Marginal fold sharp and narrow. Glabella cylindro-conical, obtusely 

 pointed in front, expanded at the base ; anterior lobe obtusely pointed, less than a third of 

 the whole length of the glabella; posterior lobe, strongly elevated and obtusely pointed 

 behind ; basal lobes triangular, depressed to the level of the cheeks. Cheeks somewhat 

 narrower in front than at the sides ; divided in front by a distinct furrow that connects 

 the dorsal and marginal furrows. Thorax unknown. 



A pygidium found in the same shale may belong to this species. It is subquadrate, 

 wider behind than before, and has a pair of cusps at the outer angles. The axial lobe is 

 nearly half as wide as the pygidium, it is about four fifths of its length and projects for- 

 ward beyond the side lobes ; it is obtusely lanceolate, somewhat narrowed in the middle 

 and divided into three lobes, of which the posterior is a half longer than the length of the 

 two anterior ; the middle lobe is elevated in the middle and bears an elongated tubercle 



