348 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



merges into the spines at the six angles, and extends inward at 

 the posterior margin to the occipital ring. 



Glabella elongate, subcylindrical, and divided by four pairs of 

 transverse furrows into four lobes and an occipital ring; the an- 

 terior lobe is nearly circular in outline, globose, and sloping down 

 from the anterior glabellar furrow at an angle of about 45°, to the 

 intermarginal space just within the wire-like marginal rim ; the 

 second lobe is broadest at the ends and narrow at the center, owing 

 to the anterior pair of furrows extending obliquely inward and back- 

 ward while the second pair of furrows are almost at right angles 

 to the sides of the glabella, and united without interruption at the 

 median line so as to form a continuous furrow across the glabella ; 

 the third and fourth lobes and occipital ring have approximatelv the 

 same width ; they are separated by the third pair of glabellar fur- 

 rows which extend inward and a little backward nearly to the median 

 line, where they are united by a more shallow, transverse furrow ; 

 on both the third and fourth lobes there is a depressed space on the 

 posterior half of the lobe that extends over about three-fifths of its 

 length ; this causes the lobe to have a raised front part connected 

 with ends that appear on the third segment like flattened tu- 

 bercles, and on the fourth segment, where the depressed space is 

 less extended laterally, as low, elongate tubercles ; when the glabella 

 is compressed laterally the ends of the second, third, and fourth 

 lobes have the tubercles or elevated ends of the lobes quite prominent, 

 these resemble the lateral tubercles on the median lobe of the thoracic 

 segments of some forms of Agnostus and Microdisciis. The ends of 

 the fourth glabellar lobe appear to be united to a low ridge that 

 extends obliquely outward and backward into the intergenal spine 

 on each side ; the first lobe is united to the palpebral lobe, while the 

 second and third lobes are connected on each side with the long inter- 

 palpebral lobe or tubercle that extends parallel to the glabella from 

 the second lobe to where it merges into the ridge connecting the 

 fourth lobe and the intergenal spine on each side. Occipital ring 

 marked by a shallow, narrow furrow that extends inward from each 

 end at the posterior margin and crosses the ring obliquely nearly 

 to the center just within the anterior margin of the ring. On the 

 broad, transversely subtriangular space thus outlined a sharp, minute 

 node occurs close to the posterior median margin of the ring. The 

 glabella is separated from the other parts of the cephalon by a dorsal 

 furrow that is of varying depth owing to the interruptions caused 

 by the low ridges crossing it from the glabellar lobes ; these ridges 



