CRUSTACEA. 89 



PRO ET I DM. 



PROETUS, Steininger. 1831. 

 Proetus Conradi. 



PLATE XX, PIG. 9. PLATE XXI. FIGS. 27. 28; IND PLATE XXII, FIG. I. 



Proetus Conradi, Hall. Descr. New Species of Fossils, etc., p. 69. 1861. 



Proitus Conradi, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., p. 97. LS62. 



Proetus Conradi, Hall. Illustration? of Devonian Fossils, pi. xx. fig. ti (not tigs. 5, S, '.)). ls7>;. 



Proetus marginaZU, Hall. Illustrations of Devonian Fossils, pi. xxi. figs. 27, 28. IS76. 



General Form and Proportions. Outline elliptical or sub-ovate: length to 

 width as 3 to 2. 



Surface convex: depressed or flattened near the longitudinal furrows. 



Cephalon semi-elliptical; length to width as 1 to 2. Border very broad, gently 

 convex toward its inner edge, sloping evenly outward and at the outer edge 

 faintly reflexed ; at the genal extremities produced into short, stout spines, 

 extending as far as the fourth thoracic segment. 



Facial Sutures normal, crossing the anterior border more directly than in 

 Prottus angustifrons. 



Glabella short, slightly longer than wide ; sub-ovoid; tangent at its anterior 

 extremity to the inner margin of the border. Surface depressed-convex, 

 slightly Rattened above. Casts of the lower surface show well-defined 

 basal lobes, and under favorable preservation the other glabellar lobes would 

 probably be apparent. Occipital furrow deep; occipital ring moderately 

 broad and elevated ; occipital lobes inconspicuous on the dorsal surface, but 

 quite large in the internal cast. 



Cheeks narrow, broadly flattened about the eyes, and abruptly deflected to 

 the marginal sulcus. The most elevated portion of the checks lies in the 

 angle made by the marginal sulcus and occipital furrow. 



