442 TWO NEW TRILOBITES FROM BOWNING, 



very gently convex and diminish in width as they pass around the 

 front of the glabella. Facial sutures follow the courses charac- 

 teristic of the genus. 



Thorax: greatest width, 57 nun., length, 30 mm,., smooth or 

 microscopically granular, mildly inflated; axis subspindle-shaped, 

 the fifth and sixth rings being the widest, and from these the width 

 gradually diminishes posteriorly, mildly convex, greatest width 

 12 mm., or about half as wide as the width of one side lobe, bases 

 of rings very slightly swollen. Side lobes very mildly convex, 

 medial furrows of somites wide and deep, the ridges of these, too, 

 are strong, the posterior ones being thickened at the ends abutting 

 the axial grooves, so as to appear mildly tuberculate; their ter- 

 minals are claw-like. 



Pyyidinm: triangular and smooth axis consists of 16 to 20 

 rings (dependent on the state of maturity), of which the last 

 two or three are faintly outlined; only mildly convex, its width 

 diminishes gradually posteriorly and terminates with less than 

 one-third of the anterior spread inconspicuously, at the border; 

 the six or more anterior rings have their bases gently thickened, 

 those posterior to these very gradually become fainter, and towards 

 the end annulations frequently seem to obsolesce; its greatest 

 spread is approximately half as great as one side lobe. Side lobes 

 mildly inflated, gradually sloping from near the axial grooves to 

 the periphery; the pairs of segments number from eleven to 

 fourteen according to the state of maturity reached by the indi- 

 viduals examined, and are very similar in structure to the thoi-acic 

 somites, their ridges, furrows and articulating sutures crossing the 

 border to the narrow, very gently thickened edge; each preceding 

 pair has an increasing backward bend, so that the last pair is 

 parallel with the axis line. Border wide, similar in convexity 

 with the pleura; inwardly its boundary is indicated by a succes- 

 sion of flue linear ridges in the furrow of each pleuron ; the under 

 surface is finely and beautifully punctate; behind the axis it is 

 continued into a short deltoid spine, that is not in any way con- 

 nected with the pygidial axis, for at the inner boundary of the 

 border, the axis vanishes. 



