DIG.] 



CRUSTACEA. 



543 



macrops, Hall, 1862, 15th Rep. N. Y. St. 



Mus. Nat. Hist., p. 59, Up. Held. Gr. 

 meeki, Walcott, 1885, Mouogr. U. S. Geo. 



Sur., vol. 8, p. 207, Lower Devonian, 

 micrurus, Green, 1832, (Asaphus micru- 



rus,) Monograph Trilobites, p. 56, and 



Pal. N. Y., vol. 3, p. 359, Low. Held. Gr. 



FIG. 998. Dalmauites limulurus. 



myrmecophorus, Green, 1835, (Asaphus 



myrmecophorus,) Supp. to Monograph 



of Tribolites, p. 16, and Illust. Devon. 



Foss., pi. 13, Up. Held. Gr. 

 nasutus, Conrad, 1841, (Asaphus nasu- 



tus.) Ann. Rep. N. Y., p. 48, and Pal. 



N. Y., vol. 3, p. 362, Low. Held. Gr. 

 ohioensis, Meek & Worthen, 1871, Proc. 



Acad. Nat. Sci. Phil., p. 91, and Ohio 



Pal., vol. 1, p. 234, Up. Held. Gr. 

 phacoptyx, Hall, 1888, Pal. N. Y., vol. 7, 



p. 31, Up. Held. Gr. 

 pleione, Hall, 1862, 15th Rep. N. Y. St. 



Mus. Nat. Hist., p. 62, and Illust. Devon. 



Foss., pi. 16, Up. Held. Gr. 

 pleuropteryx, Green, 1832, (Asaphus 



pleuropteryx,) Monograph Tribolites, 



L55, and Pal. N. Y., vol. 3, p. 356, 

 w. Held. Gr. 

 pygmaeus, Hall, 1888, Pal. N. Y., vol. 7, 



p. 56, Up. Held. Gr. 

 regalis, Hall, 1876, lilust. Devon. Foss., 



pi. 11, Schoharie grit, 

 selenurus, Eaton, 1832, (Asaphus selen- 



urus,) Geo. Text Book, p. 31, and Illust. 



Devon. Foss., pi. 12, Corniferous Gr. 

 tridens, Hall, 1859, Pal. N. Y., vol. 3, p. 



361, Low. Held. Gr. 

 tridentiferus, Shumard, 1855, Geo. Rep. 



Mo., p. 199, Low. Held. Gr. 

 troosti, Safford. Not denned, 

 verrucosus, Hall, 1863, Trans. Alb. Inst., 



vol. 4, p. 218, Niagara Gr. 



vigilans, Hall, 1861, Rep. Prog. Geo. Sur. 

 Wis., p. 51, Niagara Gr. 



werthneri, Foerste, 1885, Bull. Sci. Lab. 

 Denison Univ., p. 116. Not well de- 

 fined. 



DICELLOCEPHALUS, Owen, 1852, Geo. Sur. 

 Wis., Iowa., and Min., p. 573, (written 

 by Owen Dikelocephalus.) [Ety. dikella, 

 mattock ; kephale, head.] Cephalic shield 

 sublunate or semicircular, rather flat; 

 glabella oblong ; sides parallel, rounded 

 in front, transverse behind ; three lat- 

 eral furrows on each side, the posterior 

 two crossing the glabella and dividing 

 it into three lobes ; facial sutures arise 

 in the center of the anterior border, 

 run parallel with the same to the front 

 of the eyes, are then directed backward, 

 make a sigmoid flexure over each eye, 

 and when near the neck segment ab- 

 ruptly curve laterally, reaching the pos- 

 terior border near the posterior spines 

 of the cephalic shield ; thorax with nine 

 segments, axis narrower than lateral 

 lobes; pygidium with a flattened bor- 

 der, produced posteriorly on each side, 

 and rounded in the middle ; axis ex- 

 tended only about half the length, with 

 four to six segments, which become ob- 

 solete on the lateral lobes. Type D. 

 minnesotensis. 



affinis, Billings, 1865, Pal. Foss., vol. 1, p. 

 197, Quebec Gr. or Up. Taconic. 



angustifrons, Walcott, 1885, Monogr. U. S. 

 Geo. Sur., vol. 8, p. 42, Potsdam Gr. 



barabuensis, Whitfield, 1878, Ann. Rep. 

 Geo. Sur. Wis., p. 63, and Geo. Wis., 

 vol. 4, p. 201, Low. Magnesian Gr. 



belli, Billings, 1860, Can. Nat. and Geo., 

 vol. 5, p. 301, Quebec Gr. or Up. Taconic. 



bilobatus, Hall & Whitfield, 1877, U. S. 

 Geo. Expl. 40th Parallel, vol. 4, p. 226, 

 Potsdam. Gr. 



(?) corax, Billings, 1865, Pal. Foss., vol. 1, 

 p. 334, Quebec Gr. or Up. Taconic. 



crassimarginatus, Whitfield, 1882, Geo. 

 Wis., vol. 4, p. 344, Potsdam Gr. 



cristatus, Billings, 1860, Can. Nat. and 

 Geo., vol. 5, p. 301, Quebec Gr. or Up. 

 Taconic. 



devinei, Billings, 1865, Pal. Foss., vol. 1, 

 p. 195, Quebec Gr. or Up. Taconic. 



eatoni, Whitfield, 1878, Anu. Rep. Geo. 

 Sur. Wis., p. 65, and Geo. Wis., vol. 4, 

 p. 202, Low. Magnesian Gr. 



expansus, Walcott, 1885, Monogr. U. S. 

 Geo. Sur., vol. 8, p. 45, Potsdam Gr. 



finalis, Walcott, 1885, Monogr. U. S. Geo. 

 Sur., vol. 8, p. 89, Up. Taconic. 



flabellifer, Hall & Wf.itfield, 1877, U. S. 

 Geo. Expl. 40th Parallel, vol. 4, p. 227, 

 Potsdam Gr. 



(?)flagricaudus, White, 1874. Rep. Invert. 

 Foss., p. 12, and Geo. Sur. W. 100th Mer., 

 vol. 4, p. 60, Quebec Gr. or Up. Taconic. 



gothicus, Hall & Whitfield, 1877, U. S. Geo. 

 Expl. 40th Parallel, vol. 4, p. 242, Up. 

 Taconic. Probably a syn. for Olenoides 

 wahsatchensis. 



