4-i A CoxxraBUTiox to the Lower Devonian Faunas of Maryland 



ARTHROPODA 



subbnmch BRANCHIATA 



Class CRUSTACEA 



subcinss TRILOBITA 



Order OPISTHOPARIA 

 Family PROETIDAE 



Genus PROETUS Steininger 



Proetus cf. protuberans Hall 

 Plate LXXXIX, Figs. 2-4 



Proetus protnberans Hall, 1859, Nat. Hist. N. Y., Pal., vol. ill, p. 351, pi. Ixxiil, 

 figs. 5-8, 1861. 



Description. — " Entire form oblong elliptical. Head semicircular, ver}'- 

 gibbous; the glabella very prominent, rounded in front, not distinctly 

 lobed ; the cheeks sloping abruptly from the eyes to the outer margin : 

 posterior angles subacute (perhaps prolonged into spines iji entire speci- 

 mens) ; eyes prominent. Occipital annulation prominent; the furrow 

 strong, and marked below each posterior angle of the glabella by a small 

 tubercle. Thorax consisting of nine or ten articulations (the specimen 

 being too imperfect for actual determination). The axis is very promi- 

 nent, semicylindrical, and the lateral lobes nearly flat for a little distance 

 from their origin, and then bending abruptly downwards. Pygidium semi- 

 circular : axis very prominent, marked (in the cast) by eight annulations ; 

 lateral lobes marked by four or five ribs. Surface granulate; the anterior 

 border, and articulating surfaces of the axis striate : exfoliated surfaces 

 striate." Hall, 1859. 



Occurrence. — Helderberg Formation, Xew Scotland Member. 

 Corriganville. 



Collection. — American Museum of Xatural History. 



