40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 98 



The holotype is characterized by a cranidium that expands at about 

 the usual rate and has the usual furrows. The second pair of glabellar 

 furrows is somewhat distinctive in that it consists of deep narrow 

 slots, and the rear pair is somewhat irregular in its course. In cross 

 section this is quite a flat species with the glabella arched above the 

 dorsal furrow and the palpebral lobes flat on top, sloping off at the 

 outer edges. Longitudinally, there is greater curvature, fairly steep in 

 front, but otherwise gentle. The palpebral lobes at their widest point 

 are half the width of the glabella. The eye bands are wide and the 

 eyes are of moderate length and not greatly curved. The fixigenes 

 form a narrow flange anterior to the eyes and there is almost no rim. 

 The surface is smooth, except for irregular puckering of the test 

 near the occipital spine. 



Locality 54s. 



Holotype.— U.S.N.M. No. 98517. 



PTARMIGANIA ALTILIS, n. sp. 

 Plate 7, figs. 3-s 



This relatively small species is represented by several cranidia and 

 one libragene. The glabella expands in normal fashion, and while the 

 usual glabellar furrow r s are present, they are excessively shallow, ex- 

 cept for the anterior pair which is quite deep due to a swelling of the 

 glabellar surface near it. The head is nearly flat in cross section but 

 considerably arched longitudinally. The eyes are about normal in 

 length and considerably curved toward the rear. At their widest point 

 the palpebral lobes are slightly less than half the glabellar width. The 

 eye bands are clearly differentiated, but the palpebral furrow is 

 shallow. The test is smooth, except for linear rugosities on the occip- 

 ital ring. Anterior to the eye the fixigenes form relatively wide 

 downturned flanges, and the rim is very narrow. 



Locality 54s. 



Holotype and paraiype. — U.S.N. AT Nos. 98519a, b. 



PTARMIGANIA SOBRINA, n. sp. 

 Plate 7, figs. 12-15 



One cranidium and several pygidia have been associated to form 

 the species. A libragene lies near the pygidium and is thought to 

 belong with it. This species is characterized by a parallel-sided, rela- 

 tively long and narrow glabella. In cross section the glabella is arched 

 to a slight keel, and the palpebral lobes are quite convex, being rolled 

 over on their outer edges. Longitudinally this species has considerable 



