326 Systematic Paleontology — Middle Devoniax 



much compressed in the softer shales, has a greatest diameter of 95 mm. 

 The prevailing fonns are illustrated on plate 71. The natural rotundity 

 of the young and medium-sized specimens is illustrated in figures 5, 6, 8, 

 and 9 of the same plate. 



" This species differs conspicuously from tlie young of G. Vanuxemi by 

 its closed umbilicus, and the usual absence of undulations or annulations 

 upon the shell surface or upon the casts." Hall, 1897. 



This shell occurs rather rarely in the dark shales. The largest indi- 

 vidual observed has a maximum breadth of 47 mm. 



Occurrence. — Romney Formation, Onondaga Member. Williams 

 Road, 31/^ miles southeast of Cumberland. 



Collection. — U. S. National Museum. 



[E. M. Kindle.] 



arthropodX 



Class CRUSTACEA 



Subclass TRILOBITA 



Order OPISTHOPARIA 

 Family PROETIDAE 



Genus CYPHASPIS Burmeister 



Cyphaspis cf. stephanophora Hall 

 Plate XLII, Pig. 9 



Cyphaspis stephanophora Hall, 1888, Pal. N. Y., vol. vii, p. 142, pi. xxiv, 

 figs. 2-6. 



Description. — " Cephalon. Outline transversely semi-elliptical ; length 

 to width as 1 to 1.7. Genal angles produced into recurved spines which 

 are longer than the axial length of the cephalon. Border spinose and 

 thickened by doublure. Frontal area narrow, convex and appressed about 

 the glabella, anteriorly depressed by abrupt curvature to the thickened, 

 slightly reflexed anterior margin. 



" Facial Sutures, normal for the genus, originating on the occipital 



^Contributed by Charles S. Prosser with the addition of Onondaga species 

 by E. M. Kindle as indicated. 



