218 
AUG. F. FOERSTE 
ridge passes from the anterior pair of glabellar furrows obliquely 
backward to the palpebral lobe, or may be entirely absent. 
The axial lobe of the thorax is relatively broader and the free 
terminations of the pleural segments spread out farther than in 
Ceraurus dentatus. The strongly developed spines of the pygid- 
ium not only curve strongly backward but are even slightly 
convergent posteriorly. That part of the pygidium which is 
included between these spines resembles the pygidium of Ceraurus 
pleurexanthemus; no dentate margin is present as in Ceraurus 
dentatus. 
From the top of the Plattin limestone at the city quarry a 
mile southeast of New London, along the lower part of Big 
Creek, at the Buford Cave, and elsewhere in Ralls County. 
38. Endymionia bellatula Savage 
This species was described by Savage (Illinois Acad. Sci., 
1917, p. 273, pi. I, fig. 3) from the Thebes sandstone, near 
Thebes, Illinois. It is cited by him also from Madison Creek, in 
Calhoun County, Illinois, and from Dover church, in Pike 
County, Missouri. Prof. R. R. Rowley discovered long ago a lo- 
cality on the Goodman place, | mile west of Calumet post- 
office, where this little trilobite occurs in great abundance about 
3 or 4 feet above the base of the Buffalo shales. 
39. Nileus sp. 
Plate XXIII, fig. 4 A, B 
Eyes very prominent, attaining an elevation of 2.5 mm. in 
cranidia 15 mm. long, rising rather abruptly above the general 
surface of the cephalon, and limited on the inner side by broad 
though shallow depressions. In specimens whose palpebral 
lobes are 10 mm. apart the shallow depressions along their 
inner sides have their deepest parts about 6 mm. apart. The 
median parts of the cranidia, between these shallow depressions, 
may be regarded as the poorly defined glabella which broadens 
anteriorly and merges into the general curvature of the cranidium. 
