220 
AUG. F. FOERSTE 
line of contact with the glabella it is distinctly indented. In 
these particulars the Ralls County specimen agrees better with 
the minute specimen of Proetus figured by Ruedemann (Bull. 
New York St. Mus., No. 49, 1901, p. 62, pi. 4, figs. 5, 6, 7), 
from the Trenton (Rysedorph) of New York. 
41. Pterygometopus cf. lincolnensis Branson 
Plate XXI, fig, 19 
Pterygometopus lincolnensis Branson differs from Pterygometo- 
pus eboraceus (plate II, fig. 20, of this Bulletin) , from the Trenton 
of New York, in the absence of genal spines; the third pair of 
lateral glabellar lobes is not confluent with the second; no tubercle 
occurs on the occipital ring; the frontal lobe of the glabella is 
shorter and broader; the eyes are larger; and the fixed cheeks 
are smaller. At the top of the Plattin limestone, at the Buford 
Cave, specimens resembling Pterygometopus lincolnensis occur, 
but these have distinct genal spines. An examination of the 
types of Branson^s species suggests that better preserved speci- 
mens of the latter may also have genal spines. 
x4nother form similar to Pterygometopus lincolnensis, found in 
the Tyrone member of the Black River formation at High 
Bridge, in central Kentucky, was described by me recently as 
Pterygometopus confiuens Foerste (Ohio Jour. Sci., 19, 1919, 
p. 396, pi. 19, fig. 19). It is refigured in this bulletin as figure 
22 on plate II. It differs from the other known forms in the 
flatness of the cranidium, including all of its lobes. 
In Pterygometopus intermedius (Walcott), from the Black 
River formation of the upper Mississippi Valley, all of the lat- 
eral glabellar lobes are free (plate II, fig. 21 of this bulletin). 
42. Remopleurides missouriensis sp. nov. 
Plate XXI, fig. 17; plate XXII, figs. 17 A, B 
In the best preserved cranidium, the width of the glabella, at 
midlength of the palpebral lobes, is 7.2 mm., and each of the 
palpebral lobes is slightly over 0.2 mm. in width. The length 
of the glabella is 7 mm., and the neck segment adds 1 mm. in 
