58 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 98 



terminating very abruptly in the rear. The pleural platforms are 

 moderately convex, dropping off to the flattened border, which has 

 a horizontal position. Both the pleural furrows and grooves remain, 

 but the most conspicuous feature is the elevated rib formed by the 

 anterior half of each pleuron. The border extends into long, stout, 

 flat spines at the posterior angles. 



Locality 54s. 



Holotype and paratype. — U.S.N.M. Nos. 98558a, b. 



KOCHASPIS DISPAR, n. sp. 



Plate 13, figs. 1-4, 13-15 



At first these cranidia and pygidia were regarded as separate 

 species, but it was decided to refer the cranidia to the species based 

 on the pygidium. Since examples of Dolichometopsis occur on small 

 pieces of rock with this species, it no doubt is a member of the 

 Ptarmigania fauna. 



The glabella is stout and tapers considerably to a rounded front. 

 The dorsal furrow is deep. Three pairs of recurved glabellar furrows 

 appear strongly in proper light. A slight keel is apparent on some 

 specimens. The fixigenes are convex rising from the dorsal furrow 

 and then curving down slightly to the eyes, which are rather promi- 

 nent. The rim is almost equally divided between the slightly convex 

 preglabellar area and the thickened rim. Longitudinally the cranidium 

 is convex, with the greatest curvature in the fear and the whole for- 

 ward half of the head sloping down rather sharply but without much 

 curvature. Eye lines heavy. Surface slightly granulose ; brim verti- 

 cally striated with faint irregular lines. 



The pygidium is much like that of Vanuxemclla, except that it is 

 larger and that fusion has not completely eliminated the pleural 

 markings. 



The axis is stout and stands above the pleural platforms. Three 

 axial furrows and the terminal segment are clearly defined. The axis 

 has very steep slopes at the sides but the curvature is somewhat 

 flattened on top. It terminates abruptly, but there is a slope to the 

 rear margin. Fusion has reduced the pleural grooves to very shallow 

 furrows, but the pleural furrows are more clearly defined. As in 

 K. malailcnsis the anterior rib of each pleuron is elevated. The tail 

 is wide, and hence the slightly thickened rim extends into spines 

 which are set wide apart, more in the manner of Vanuxemclla than 

 of Kochaspis. These spines are short. 



Locality 59c 



Holotype and paratypes. — U.S.N.M. Nos. 98559a-d. 



