Vol. 69.] OF THE COMLEY BRECCIA-BED. 35 



point about two-thirds out from the glabella; extended laterally to 

 a greater distance than the eye-lobe. 



Pro nt. — Hounded at the apex of the glabella, but almost straight 

 from it to the sutures; consisting of a narrow marginal fold, 

 separated from the glabella and cheeks by a sharp and narrow 

 groove; towards the sutures both fold and groove widen and tend 

 to die away. 



Pacial suture. — Anterior branch, as seen from above, almost- 

 parallel to the axial line, but curved inwards at its termination to 

 join the anterior margin tangentially. Posterior branch strongly 

 divergent, but also curving inwards at its termination to join the 

 posterior margin tangentially. 



Pree cheek. — When attached to the cranidium, the free cheek 

 would be foreshortened in width, and show but a small area in 

 the view from above (PI. Ill, fig. 1 a) ; but, as seen lying in the 

 rock (tigs. 6 & 7), it is nearly as wide, opposite the eye, as the fixed 

 •cheek. It consists of two parts sub-equal in width: (i) an inner 

 convex area concentric with the eye, and (ii) a wide, convex mar- 

 ginal fold, which is the continuation in an expanded condition of 

 the front marginal fold of the cranidium ; the two parts of the 

 free cheek are separated by a wide but ill-defined hollow, which 

 connects the anterior and posterior marginal grooves of the crani- 

 dium ; the genal angle is produced to form a rather short spine, 

 about half the length of the outer border of the cheek ; in conse- 

 quence of the curved course of the posterior termination of the 

 facial sutnre, a sharp point is left on the cheek between the suture 

 and the base of the spine. 



Test. — The surfaces of the glabella and cheeks are covered with 

 •a bold pattern of reticulate, raised lines, beautifully shown in the 

 specimens retaining the test [1882, 141 1 ] (PI. Ill, tigs. 2 & 5). No 

 trace of this is seen on the internal casts, but on the external casts 

 the same pattern is often traceable as a network of impressed lines, 

 •enclosing roughly hexagonal, or rounded prominences (fig. 1 c). On 

 the sides of the glabella the reticulations tend to become parallel with 

 its margin, and are interrupted at the places where the glabellar 

 furrows might be expected to occur (fig. 2). On the marginal 

 ifold the reticulations are elongated, and give rise to a system of 

 anastomosing raised lines (fig. 5). 



The furrows appear to be smooth. 



Hypostoma (PI. Ill, figs. 8, 9 a, & 9 &).— Pour fragmentary 

 -examples of hypostomas from the same rock-bed may be referred to 

 'this species [1535, 1812, 1813 and 1816, 1814 and 1815]. 



In general form the hypostoma is rather closely comparable to 

 that of Olenoides ellsi Walcott 1 ; but the points of the wings are set 

 farther back. 



The body of the hypostoma is very convex and of an elongated 

 oval form, about twice as long as wide, and a little narrower 



1 10th Ann. Rep. U.S. Geol. Surv. 1888-89 (1890) pp. 643, 644 & text- 



i)2 



