328 Systematic Paleontology — ^Middle Devonian 



Order PROPARIA 

 Family CALYMMENIDAE 



Genus HOMALONOTUS Koenig 



HoMALONOTus DEKAYi (Green) 



Plate XLIII, Figs. 1-7 



Dipleura dekayi Green, 1832, Mon. Trilobites N. A., p. 79. 

 Dipleura dekayi Vanuxera, 1842, Geol. N. Y., pt. iii, p. 150, fig. 1. 

 Homalonotvs dekayi Emmons, I860, Man. Geol., p. 146, figs. 134, 135. 

 Homalonotus dekayi Hall, 1802, Fifteenth Rep. N. Y. State Cab. Nat. Hist, 



p. 113. 

 Homalonotus dekayi Hall and Clarke, 1888, Pal. N. Y., vol. vii, p. 7, pi. ii, 



figs. 1-11; pi. iii, figs. 1-5; pi. iv, figs. 1-6; pi. v, figs. 1-10. 

 Homalonotus dekayi Keyes, 1891, Johns Hopkins Univ. Circ, vol. xi, p. 29. 

 Homalonotus (Dipleura) dekayi Clarke, 1903, N. Y. State Mus., Bull. 65, 



p. 712. 

 Homalonotus dekayi Grabau aad Shimer, 1910, N. Am. Index Fossils, vol. ii, 



p. 318, fig. 1631. 



Description. — General from elongate, lingniform, anterior and posterior 

 extremities produced and subangulate; lateral margins nearly straight 

 and approximating posteriorly; length to width about as two to one. 

 Surface depressed-convex or flattened, obscurely trilobate, abruptly de- 

 flected along the lateral margins. Cephalon broadly subtriangnlar in out- 

 line, posterior side the longest; angles rounded; glabella subquadrang- 

 ular, broadest behind; movable cheeks flattened and when normally pre- 

 served abruptly deflected; eyes situated at the summit of strong, elevated 

 nodes. Thorax broad, length equal to the width; surface depressed- 

 convex; scarcely trilobate, lateral portions abruptly deflected; axis broad, 

 making two-thirds the width of the body; pleurae narrow, deflected along 

 their median line. Pygidium subtriangular, anterior margin with a for- 

 ward curve, lateral margins neaiiy straight, with an upward curve near 

 the posterior extremity, which is produced into a subspatulate extension; 

 surface convex, faintly trilobate; ten annulations on the axis and eight 

 upon the pleurae, which are rarely visible upon the dorsal surface except 

 in young individuals. The surface of the test on its more prominent 

 portions marked by the openings of large vertical tubulipores, the edges 



