70 North Awcrican 



with six or seven segments separated by shallow, but well marked furrows! 

 surface thickly studded with granular, whicli are rather smaller than those 

 of the glabella." 



Locality. — Lithographic Limestone (Waverly series), at Hannibal, Louisi- 

 ana, and Chouteau Springs, Missouri ; also at Granville, Ohio. 



In the Lower Carboniferous Group of North America we have seven spe- 

 cies of the genus Proetus, viz. : Proetus auriculattis Hall, extending up from 

 the Chemung into the Waverly series, and the following species from the 

 Waverly series : P. Mismuriensis, Slmmard ; P. Loganensis, Hall and Whit- 

 field ; P. peroccidens, Hall and Whitfield ; P. triniicleatus, Herrick ; P. ? 

 ellipticus, Meek and Worthen ; P. Tennesseensis, Winchell. 



We have examined several cephalic ^h'\Q\([^ oi Proetus Missouri- 

 ensis from Hannibal, Missouri, now in the American Musenm of 

 Natural History, New Yoi'k City. The glabella of the lai-ge^t 

 specimen measures 15 mm. in width across its broadest portion, 

 and about the same in length ; the occipital ling is well defined, 

 sei)arated fi-om the ghibella by a prominerjt occipital sinus. 



Another specimen, in the Columbia College collection, from 

 Cameron, Missouri, shows the ^'labella and one movable cheek. 



7 7 C 



The movable cheeks are sub-triangular in outline and liiglily 

 convex ; the eyes being located high up on the cheeks ; the cheeks 

 slope from tlie eyes at an angle of about 45° to half their width. 

 At this point they are slightly dejiressed, then gradually slope off 

 to the marginal border; the limit or marginal border of the 

 head consists of a- nari'ow raised band extending around tlie head. 

 T'he genal angles ajipear to be obtusely rounded off. The facial 

 suture cro.^ses the frontal border slightly outside of a line drawn 

 parallel with the outside of the eyes, above which it ex])ands, 

 forming a rounded ])alpebral lobe ; then ])assing down, it diver- 

 ges outwards and ci'osses the posterior border obliquely behind 

 the line of the orbit. The fixed cheeks expand both before and 

 behind the eyes. 



This specimen, being an internal cast, exhibits two peculiar 

 cone-like elevations instead of pores; they are in front of the 

 eyes on the dorsal furrows of the glabella ; the fixed cheeks at 

 this point are slightly depressed into an oblong hollow, rounding 

 oft' and cutting into the sides of the glabella. The upper shell 

 of tlie specimen has been removed, and we have here the interior 

 impressions of these auxiliary impressions, as Bairande calls' 

 them. These peculiar i)ores placed on each side of the glabella? 



