THE NATURAL HISTORY SURVEY. 245 



backward and inward, nearly parallel with the dorsal furrows 

 to a point just back of the line joining the eyes, where they 

 are continuous with the third lateral furrows, making a sharp 

 turn outward and forward around the posterior extremities 

 of the anterior lateral lobes, this inner well-defined portion of 

 the third lateral furrows is short, being continued obliquely 

 forward to the dorsal furrows as slight depressions which are 

 sometimes almost obsolete; second lateral furrows represented 

 by slight indentations of the anterior furrows into the inner 

 sides of the anterior lateral lobes at about the middle of their 

 length; anterior lateral lobes compound, sub-elliptical in out- 

 line, the longer axis a little more than twice the shorter, directed 

 outward and forward, confluent posteriorly towards the dorsal 

 furrow with the third lateral lobes; third lateral lobes much 

 smaller than the anterior ones, ill-defined, separated from the 

 median lobe by slight depressions only, which may sometimes 

 be almost obsolete, from the anterior lateral lobes they are 

 sharply separated within but laterally towards the dorsal fur- 

 rows they are almost wholly confluent. Occipital furrow shal- 

 low, rather broad and ill-defined in the center, becoming more 

 strongly defined laterally where it divides, the two divisions 

 on each side surrounding a small, sub-ovate or slightly sub- 

 rhombic occipital lobe. Occipital segment rather broad and 

 flattened in the middle, a little narrower and more convex 

 laterally. Fixed cheeks very narrow in front of the eyes, con- 

 nected anteriorly around the front of the glabella by a narrow, 

 flat, marginal border, back of the eyes they are much broader 

 and are produced laterally,* they are crossed near the posterior 

 margin by the well-defined posterior cheek furrows, between the 

 eyes and the posterior cheek furrows the surface is gently con- 

 vex and slopes laterally and posteriorly. Palpebral lobes small, 

 free cheeks unknown. 



The thorax is represented in the specimens studied only 

 by detached and broken segments. The axis is apparently 

 broad and depressed-convex. 



Pygidium depressed-convex, semi-elliptical in outline; 

 the axis depressed, but little elevated above the surface of the 

 pleura, occupying more than, one-third of the entire width 

 of the pygidium anteriorly, crossed anteriorly by two trans- 

 verse furrows, the first of which is much better defined and 

 continuous across the entire width of the axis, the second one 

 is less sharply defined, and is not continuous across the median 

 portion of the axis, each of the two lateral portions curving 



