RAYMOND AND BARTON: AMERICAN SPECIES OF CERAURUS. 539 



important of their specific characters, is really due to a deformation 

 of the specimen. Measurements have failed to confirm the statements 

 of Miller and Gurley that this Ceraurus has a shorter cephalon, wider 

 frontal lobe on the glabella, or a wider and less convex thoracic axis 

 than C. pleurexanthemus. Their other points, the shorter and thicker 

 spines on the cheeks, and the thicker and straighter spines on the 

 pigidium, we believe to be well taken, and we would add to them the 

 less convex glabella and the lower eyes, whose position is further back 

 than in C. pleurexanthemus. In the matter of the position of the eyes, 

 C. milleranus is intermediate in position between C. pleurexanthemus 

 and C. dentatus. In C. pleurexanthemus the eye is further from the 

 posterior margin of the head than from the glabella. In C. milleranus 

 it is equidistant from the posterior margin and the glabella, while in 

 C. dentatus it is nearer the posterior margin than the glabella. 



The part of the pygidium of C. milleranus which is between the great 

 spines has a rather undulate marginal outline. The second segment 

 sends off short spines which extend beyond the margin, but they are 

 so short and blunt that they merely make an undulation on the margin. 

 All the specimens seem to be of this same type. The pygidia are, in 

 this respect, very unlike those of C. dentatus, but similar to a part 

 of the specimens of C. pleurexanthemus. 



Measurements. — Ceraurus milleranus is of about the same size as 

 C. pleurexanthemus and about the same general proportions. The 

 type is 39 mm. long without the pygidial spines, or 45.5 mm. long with 

 them. The width at the genal angles is 22 mm., the cephalon is 

 9 mm. long, the glabella 7 mm. wide at the front and 6 mm. wide at the 

 neck-ring. A larger cephalon is 13 mm. long and 31 mm. wide. 



Formation and Locality. — This species has been reported only 

 from the Lorraine in the vicinity of Cincinnati. Cumings (32d Ann. 

 rept. Indiana state geol. surv., 1908, p. 1059) records a pygidium of 

 Ceraurus from the Lorraine at Manchester, Indiana, which may 

 possibly be this species. 



Ceraurus misneri Foerste. 



Ceraurus misneri Foerste, Bull. Denison univ., 1909, 14, p. 228, 

 pi. 4, figs. 7A, 7B. 



The holotype of this species was found in the Whitewater bed of the 

 Richmond at Richmond, Indiana. It appears, from the photographic 

 illustrations given by Dr. Foerste, to be closely allied to Ceraurus 

 milleranus, but differs in having a longer cephalon, a more rapidly 



