156 SIXTEENTH REPORT ON THE CABINET OF NAT. HISTORY. 



tremely oblique, the middle ones less so, and reaching not 

 more than one-third across; the anterior furrows not distinctly 

 seen. Occipital furrow shallow, of equal width throughout, or 

 sometimes nearly obsolete at the extremities and a little wider 

 in the middle : occipital ring having about the same convexity 

 as the back part of the glabella. Dorsal furrow Avell defined, not 

 sharp or deep, and continuing of the same depth in front of the 

 glabella. 

 Fixed cheeks narrow. The line of the facial suture, from the front 

 contour, is nearly vertical (with the exception of the palpebral 

 curvature) to the posterior glabellar furrow, whence it turns 

 obliquely outwards, leaving a narrow posterior limb, which has 

 a lateral extension two-thirds as great as the width across the 

 axis at the occipital ring : frontal limb regularly convex, and 

 curving abruptly downwards in front. 

 Movable cheek moderately convex, more than half as Avide as 

 long, with regularly curving outer margin and thickened border 

 which is produced anteriorly, and the posterior extremity ex- 

 tends in a slender spine. Sinus, formed by the eye-tubercle, of 

 medium size. 



In two specimens, carefully measured, we have the entire length 

 of glabella 0*30 of an inch ; width of glabella at base, 0*29 ; at 

 apex, 0*18; entire length of head, 0*44; frontal limb, 0*10 of an 

 inch. In another specimen, these measures are respectively 0*25, 

 0-23, 0-14, 0-38, 0-09. 



This species, in its glabella and frontal limb, somewhat resembles C. 

 eryon (fig. 16), but the proportions are somewhat difi'erent : the glabella 

 is narrower at base and much more convex ; the frontal limb is not quite 

 so extended, and is more convex ; the facial suture continues its vertical 

 direction farther down, leaving a narrower posterior limb of the fixed cheek. 



The heads and cheeks of this species, in the condition represented on the 

 plate, occur in myriads in certain layers at Marine mills : the slabs are 

 covered with these, and remains of two other species which are compara- 

 tively rare. This position, according to Dr. Owen, is above the middle of 

 the Sandstone series in the Fourth Trilobite bed. 



The Conocephalites ( LonchocephalusJ chii^pewaensis of Owen is cited by 

 that author as occurring in the fourth or Marine-mills Trilobite grit ; and 

 before I had critically examined this one, I supposed the smaller specimens 

 to be the same. After having studied numerous specimens without finding 

 evidence of a spine from the occipital ring ( that being a conspicuous feature 

 of the C. cMppeicaenaia) , I am constrained to refer the specimens to some 

 other species. Most of the specimens, moreover, are much larger than the 

 figures of Dr. Owen. 



