232 THE CHICAGO ACADEMY OF SCIENCES. 



lobes, approximately, 5.7 mm., length of glabella and occipital 

 segment 4.25 mm., convexity of glabella 1.2 mm. 



Remarks. This species is somewhat closely allied to C. 

 christyi Hall, from Waldron, Indiana, but it may be distinguished 

 from that species by the proportionately more elongate glabella, 

 that portion of the head in C. christyi being described as one- 

 half the length of the head, while in C. intermedia it is usually 

 a little more than three-fourths of the total length of the head 

 The species differs from C. clintonensis Foerste, described from 

 the Clinton formation of Ohio and elsewhere, in its proportion- 

 ately shorter glabella, the glabella of that species reaching to 

 the innerside of the marginal border. C. intermedia, therefore, 

 occupies a position between C. christyi and C. clintonensis in 

 respect to the proportionate length of the glabella. 



Locality. Channahon, Will County, Illinois. 

 Family 4. BRONTEIDAE Barrande. 



"Dorsal shield broadly elliptical. Cephalon less than one- 

 third the entire length; glabella rapidly expanding in front, with 

 faint indications of lobes. Free cheeks larger than the fixed- 

 Facial sutures extending from the posterior margin just behind 

 the eyes abruptly inward around the palpebral lobes, and then 

 diverging and cutting the antero-lateral margins separately. 

 Eyes crescentic. Thorax of ten segments, with ridged pleura. 

 Pygidium longer than cephalon or thorax; axis" very short, 

 with radiating furrows extending from it across the broad limb 

 toward the margin ; doublure very wide ; margin generally entire . ' ; 

 Beecher, Zittel-Eastman Text Book of Paleontology, p. 631. 



Genus 6. BRONTEUS Goldf., 1839. 

 Entire body brbadly elliptical. Cephalon sub-semicircular; 

 glabella rapidly expanding anteriorly, lateral furrows and lobes 

 more or less obsolescent; eyes crescentic, situated back of the 

 middle of the head, their outer margin usually being about in 

 line with the lateral margins of the broad anterior portion of the 

 gjlabella, free cheeks larger than the fixed. Thorax with ten 

 segments. Pygidium very large, semi-circular or semi-elliptical 

 in outline with entire margin, usually longer than the cephalon or 

 thorax; axis very short with radiating furrows extending from 

 its margin across the broad, flattened pleural surfaces toward 

 the margin; doublure very wide. 



Bronteus acamas Hall, pi. xx, fig. 1. 



Description. Cephalon broad, depressed-convex, dorsal 

 furrows extending a little more than one-third the entire length 



