NO. 24 PTARMIGANIA STRATA RESSER 43 



CLAVASPIDELLA Poulsen, 1927 

 CLAVASPIDELLA WASATCHENSIS, n. sp. 



Plate 8, figs. 15-20 



Numerous pygidia, but only one cranidium, of this species have 

 been found. Parts of other cranidia are to be seen on some of the 

 larger pieces of rock. 



The glabella expands rapidly in the anterior third and is nearly 

 parallel-sided opposite the palpebral lobes. The occipital and rear 

 pair of furrows are well impressed, but the remaining furrows are 

 barely visible. There is a small node of the neck ring. Anterior to 

 the eyes the facial suture diverges rapidly, but the flanges thereby 

 produced increase little in width toward the anterior angles. Brim 

 consisting of a very narrow rim only. Palpebral l@bes are narrow, 

 being less than half the glabellar width at the same point, and they 

 maintain their width throughout nearly all of their length. The 

 pygidium is typical of the genus with its narrow axis on which four 

 rings are traceable, beside the long tapering rear segment. The pleural 

 lobes slope down to a slightly flattened border across which the pleural 

 furrows extend to the margins. Pleural grooves are faintly visible. 

 The libragene has a wide concave border, which extends into a long, 

 broad, genal spine. The surface is covered with very fine granules 

 and as usual, when the test is exfoliated, is punctate. 



Locality 20x. 



Holotypc ad paratypes. — U.S.N.M. Nos. 985263^. 



CLAVASPIDELLA EXCAVATA, n. sp. 

 Plate 9, figs. 1-6 



This beautiful species is represented by a number of specimens. 

 The glabella is long and narrow, expanding in the usual manner, with 

 ordinary development of glabellar and occipital furrows. In cross 

 section there is little convexity, except that the anterior angles and 

 the posterolateral limbs are depressed. Longitudinally curvature is 

 confined to the anterior third of the glabella. The palpebral lobes at 

 their widest point are less than half the glabellar width. They rise 

 somewhat from the dorsal furrow but do not have great convexity. 

 The palpebral furrow is clearly defined. The eye is of normal size 

 and position. The suture anterior to the eye diverges rapidly to form 

 triangular anterior angles. The associated hypostoma has the large 

 heavy bar characteristic of the genus. The pygidium is quite distinc- 

 tive both in its relief and development of furrows. The axis has 



