CEPHALASPIDyE. 57 



Sfraiir/raphical PosUion. — The Milestones (the fine-textiirerl deposit occuiTing near 

 Ludlow). 



Fig. 30. 



Diagram outlines of head-shielJ of Auchenaspis Salteri and Au. Egertoni. 



Cliaracters. — This speeies is distinguished by its small size and by the small diver- 

 gence of its lateral cornua. The surface-ornament is not known. 



General Remarks. — I have had but few^ specimens of this species to examine. I 

 think that the uniformly small size of the specimens from Ludlow, whence Sir Philip 

 Kgerton's type was obtained, as also the difference in the apparent curvature of the 

 anterior portion of the shield and its less divergent cornua, justify the separation of 

 this form from that which occurs in some abundance in the micaceous grits of the Led- 

 bury Passage-beds. 



2. Auchenaspis Egertoni. PI. XIII, figs. 3, 4, 5. 



Name. — After Sir Philip de Malpas Grey Egerton, Bart., the author of the genus. 



Stratigraphical Position. — The Ledbury Passage-beds, or ' Auchenaspis-grits.' 



Characters. — Compare the woodcut outUnes of the two species, figs. 29 and 30. The 

 three specimens of this species drawn in PI. XIII are variously imbedded in the matrix, 

 one showing more of the cornua than another. The specimen which is intended to be repre- 

 sented in fig. 3 is the most characteristic, but has not been well drawn on the plate. 

 The cornua are largely developed and diverge from the posterior or neck-plate ; the 

 shield has more than twice the vertical diameter of the preceding species. The surface 

 shows in some specimens tubercular ornament of relatively very large size. 



General Bemarks. — This species used to be almost abundant at Ledbury in the grey 

 micaceous grits which were exposed in the raihvay-cutting on that side of the ]\Ialvern 

 and Hereford Railway-tunnel. Mr. Brookes, well known to many as a clever collector 

 and a working-man of great intelligence, sometimes obtained four or five of these heads 

 on one hand-specimen of the stone; they occurred associated with fragmentary remains 

 of Ilemici/chtftpis ^fnrchisoni. 



