2l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



The type of this species is a cranidium with the occipital spine 

 broken off. Whitfield also had two associated free cheeks for 

 study. In 1898 I collected from about the same horizon in the 

 Gallatin limestone a number of fine cranidia, also fragments of an 

 associated pygidium. This material shows a strong resemblance 

 between the cranidia of C. tripunctatus and C. texanus, the difference 

 being in the thickened occipital ring and occipital spine of C. tri- 

 punctatus. The outer surface of the latter species is also more 

 thickly covered with smaller granulations. The test appears to be 

 finely punctate. 



The variation in the width of the frontal border of the two species 

 is similar, the smaller species having a proportionally narrower 

 border than the large ones. 



The closely related C. tripunctatus magnispimis differs from this 

 species in having slightly narrower fixed cheeks and a much stronger 

 and larger occipital spine. 



Formation and locality. — Upper Cambrian: (ssSd) Gallatin lime- 

 stone; Moss Agate Springs near Camp Baker, which is 18 miles 

 (28.8 km.) northwest of White Sulphur Springs, Meagher County; 

 also (4r) Gallatin limestone on ridge between Luce and Deep Creeks, 

 8 miles (12.8 km.) east of Yellowstone River and 3 miles (4.8 km.) 

 north-northeast of Mount Delano, Park County, both in Montana. 



CREPICEPHALUS TRIPUNCTATUS MAGNISPINUS, new variety 



Plate 33, figs. 2, 2a-c 



This fine species is abundant at one locality in eastern Tennessee. 

 It is the representative in the Appalachian area of C. tripunctatus 

 of the Cordilleran area, and differs from that species in its narrower 

 fixed cheeks and longer and stronger occipital spine. Both forms 

 have the outer surface of the cranidium and free cheeks rather 

 thickly dotted with irregularly arranged granules or small tubercles ; 

 the test appears to be finely punctate. 



The associated pygidia are narrow with a long, strong, nearly 

 straight spine projecting from the postero-lateral side of each pleural 

 lobe. The axial lobe is broad and divided into three rings and a 

 terminal section by strong backward-curving furrows. 



Formation and locality.— Upper Cambrian: (107) Maryville lime- 

 stone; Bull Run Ridge, northwest of Copper Ridge, 11 miles (17.6 

 km.) northwest of Knoxville, Knox County, Tennessee. 



