CRUSTACEA. 
49 
[s.-G.] ODONTOCEPHALUS, Conrad. 1840. 
Dalmanites (Odontocephalus) selenurus. 
PLATE XI B, FIGS. 15-21; and PLATE XII, FIGS. 1-13. 
AsapTius selenurus, Eaton. Geological Text Book, p. 31, pi. i, fig. 1. 1832. 
Calymene? odontocephala. Green. Monog. Ti'ilobites of North America, Snppl., p. 9. 1832. 
Odontocephalus selemirus, Conrad. Third Ann. Rept. Palaeontological Dept. N. Y. Survey, p. 204. 1840. 
Odontocephalus selenurus, Vanuxbm. Geology of N. Y., Survey Third Geol. Dist., pp. 139, 140, fig. 1. 1842. 
Odontocephalus selenurus, Hall. Geology of N. Y., Survey P'ourth Geol. Dist., p. 175, fig. 1. 1843. 
Dalmania selenurus. Hall. Twelfth Rept. N. Y. State Cab. Nat. Hist., xi- 88. 1859. 
Dalmania selenurus. Hall. Descr. New Sxiecies of Fossils, etc., x”*. 56. 1861. 
Dalmania selenurus. Hall. Pdfleenth Rept. N. Y. State Cab. Nat. Hist., x:)- 84. 1862. 
Odontocephalus - ? {Dalmanites (Odontocephalus) arenarius. Meek and Worthen. Geol. Surv. Illinois, 
vol. iii, X’P- 416, 417, x:>l. ix, fig. 10. 
Dalmanites selenurus, Hall. Illustrations of Devonian Fossils, x^l- xii, figs. 12-14. 1876. 
Dalmanites JEgm'ia, Hall. Illustrations of Devonian Fossils, pi. xii, figs. 1, 2, 7. 1876. 
Dalmanites coronatus, Hall. Illustrations of Devonian P’ossils, x)l. xii, figs. 15, 16. 1876. 
General Form and Proportions. Outline elliptical or eloiigate-sub-ovate; 
anterior and posterior margins ornate. Length somewhat less than twice 
the width. 
Surface depressed-convex above, lateral slopes abrupt. Cephalon, thorax 
and pygidimn to one another in length as 1 to 1.3 to 1. 
Cephalon. Outline sub-semielliptical, somewhat produced in front; length 
about one-half the width. Surface convex, sloping abruptly in front and 
at the sides. Border moderately broad, horizontal in front and composed of 
nine conspicuous incisor-like processes, the strongest of which is central, 
with four on either side, which become regularly smaller as the margin nar¬ 
rows backwards, the terminal one standing just in front of the lateral ex¬ 
tremities of the frontal lohe of the glabella. These tooth-like extensions 
are narrow and constricted at their bases, but widen rapidly so that they 
come in contact at the outer margin, though remaining entirely discrete. On 
the cheeks the border is broadly grooved and sloping, thickened along the 
outer and inner boundaries, and at the genal angles rounded or produced 
into a short, inconspicuous spinule. 
