334 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



a little larger longitudinally than the second lobe ; the second, third, 

 and fourth lobes all arch backward at the center where they are 

 most convex and rounded so as to give the impression of a longi- 

 tudinal ridge extending from the base of the first lobe backward and 

 across the occipital ring, where it terminates in a minute node ; the 

 extensions of the second and fourth lobes into the interpalpebral 

 lobe space suggest the primitive segmentation of the cephalon, as 

 shown in the young pf Elliptocephala asaphoid.es [pi. 25, figs. 9 

 and 10], and Pcedeumias fraiisitans [pi. 25, fig. 22]. On the largest 

 cephalon, 11 mm. in length, there is a faint, shallow, narrow groove 

 on each side in advance of the palpebral ridge just within the base 

 of the anterior glabellar lobe that outlines a very narrow ridge some- 

 what similar to that of Callavia crosbyi [pi. 28, fig. i], except that 

 it is not as clearly defined. Occipital ring rounded, prominent, 

 arched a little backward, and with a minute, median, sharp node on 

 a longitudinally elongated base. 



Palpebral lobes narrow, slightly rounded, gently curved, con- 

 nected to the first glabellar lobe by a rounded ridge and terminating 

 posteriorly opposite the ends of the fourth pair of glabellar furrows 

 at about the width of the palpebral lobe from the dorsal furrows 

 beside the glabella ; the lobes rise to nearly the level of the median 

 line of the glabella and cap the visual surface of the eye, which 

 rises abruptly from the cheeks ; interpalpebral space depressed and 

 separated from the third and fourth lobes of the glabella by a very 

 faint dorsal furrow ; visual surface of eye narrow and arching be- 

 neath the outer edges of the palpebral lobe. Cheeks of medium 

 width and rising rather abruptly from the intermarginal furrow to 

 the base of the eye ; nothing can be seen on the outer surface indi- 

 cating a facial suture, but the cast of the inner surface shows a 

 narrow ridge extending from the posterior end of the eye outward 

 and backward so as to cross the marginal border at about two-thirds 

 of the distance from the occipital ring to the genal angle. 



Surface beautifully ornamented by a fine network of very narrow, 

 slightly elevated ridges ; on the marginal border the meshes of the 

 network are elongated subparallel to the border ; on the large first 

 lobe of the glabella the long axes of the meshes curve around sub- 

 parallel to the anterior margin of the lobe ; over the remaining por- 

 tions of the surface no marked direction is noted as the meshes are 

 irregular in form and arrangement ; the inner surface of the checks 

 shows the cast of a system of irregular channels extending outward 

 from the base of the eve toward the intermarginal groove. 



