CRUSTACEA. 
37 
of the latter species was accompanied by a figure, no violence is done to Mr 
Conrad’s determinations by according recognition to the latter name. 
Distribution. Upper Helderberg group. Corniferous limestone : near Clarks¬ 
ville, Albany county ; Schoharie, Schoharie county ; Caledonia, Monroe county ; 
Lime Rock, near LeRoy, Genesee county ; Clarence, Erie county; Falls of the 
Ohio, Columbus and Marblehead, Ohio. 
Dalmanites (Cokonura) myrmecophorus. 
PLATE XI A, PIG. 13; PLATE XIII, PIG. 12; PLATE XIV, FIGS. 1-6; and PLATE XV, FIGS. 1-4. 
Asaphus myrmecophorus, Green. Siijipl. Monog’. Trilob. North America, p. 16. 1835. 
Asaphus? acanthopleurus {acantlioleuncs, in error), Conrad. Fifth Ann. Rept. Pal. N. Y., p. 48. 1841. 
Dalmania myrmecophorus. Hall. Descr. New Species of Fossils, etc., p. 60. 1861. 
Dalmania myrmecophonis, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., p. 88. 1862. 
Asaplms? acantholeurus, (Conrad) Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., p. 113. 1862. 
Dalmanites myrinecophor^is, Hall. Illustrations of Devonian Fossils, pi. xiii, figs. 15, 16. 1876. 
Dalmanites acantholeurus. Hall. Illustrations of Devonian Fossils, pi. xix, fig. 14. 1876. 
The Cephalon and Thorax of this species have been observed only in a condi¬ 
tion so fragmentary as to be unsatisfactory for description or positive 
identification. 
Pygidium large, sub-ovate-triangular, broadly emarginate behind. Surface 
depressed-convex, scarcely flabellate, conspicuously trilobate. Posterior 
limbus with an upward curve, which begins at the posterior third of the 
shield and terminates in a vertical spiniferous border. 
Axis relatively narrow, width about one-fifth the width of the shield upon 
the anterior margin; evenly tapering to a termination which becomes obso¬ 
lete within the posterior border. Composed of sixteen to nineteen broad 
transverse annulations, separated by narrow, deep furrows. 
PleurtE broad, most convex at about one-third their width from the axial 
margins, thence rapidly sloping and becoming somewhat flattened near the 
edge; composed of fifteen to eighteen broad annulations, which widen 
toward their distal extremities, and in some instances show traces of a faint 
