NO. 3 CAMBRIAN AND OZARKIAN TRILOBITES 79 



Cephalon semi-circular in outline. Glabella smooth, tapers slightly 

 to rounded front, a little more than half the length of the cranidium. 

 Occipital furrow present, dorsal furrow strongly impressed. Frontal 

 limb consists of a border and a fairly wide rim. The course of the 

 facial suture is unusual : back of the eye it turns directly outward 

 and somewhat forward, making a postero-lateral limb that is wider at 

 its outer extremity than immediately below the eye. In front of the 

 eye the suture turns outward very sharply as does the posterior 

 portion. It is intramarginal for about half the distance between the 

 anterior corners of the cranidiimi and the center. A cranidium 

 viewed with the free cheek separated exhibits the characters of a 

 Proparian trilobite, in which the facial suture cuts the margin anterior 

 to a rounded genal angle. When, however, this free cheek with its 

 long genal spine is studied, its true course, which is illustrated by 

 figure 24, plate 17, becomes clear. It is also not unlike that of the 

 Hypoparian Triniiclcus in the manner of rounding the genal angle. 

 The facial suture is usually so tight in most species that the free cheeks 

 are seldom separated. 



The thorax of the genotype has seven segments. 



The pygidium is nearly as large as the ceplia'.on. It is semi-circular 

 m outline and has a sloping border: axis convex with four or five 

 segments that continue across the pleural lobes to merge into the 

 border. 



Surface smooth or slightly roughened by fine depressed granulations. 



Genotype. — Cedaria prolifica Walcott. 



Range.- — Upper Cambrian : Appalachians, Wisconsin. 



CEDARIA PROLIFICA Walcott 



Plate 17, figs. 18-21 



Cedaria prolifica Walcott, 1924, Smithsonian Misc. Coll., Vol. 75, No. 2, p. 55, 

 pi. 10, fig. 6. 



The generic characterization together with the figures present the 

 features of this species. 



Formation and locality.— Upper Cambrian: (91) Conasauga for- 

 mation. Cedar Blufi^, Cherokee County, Alabama. 



CEDARIA TENNESSEENSIS, new species 



Plate 17, figs. 22-25 



Obserz'afions. — This species dififers from C. prolifica in the wider 

 postero-lateral limbs and the wider frontal limb of the cranidium. 



