528 



CRUSTACEA. 



[AMP. ANT. ' 



canadensis, Billings, 1859, Can. Nat. and 



Geo., vol. 4, p. 381, Chazy Gr. 

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



p. 322, Quebec Gr. 

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



p. 290, Quebec Gr. 

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



290, Quebec Gr. 



matutinus, Hall, 1863, 16th Rep. N. Y. 



St. Mus. Nat. Hist., p. 222, Potsdam Gr. 



mullisegmentatus, see Encrinurus multiseg- 



mentatus. 

 nevadensis, Walcott, 1885, Monogr. U. S. 



Geo. Sur., vol. 8, p. 94, Chazy Gr. 

 salteri, Billings, 1861, Can. Nat. and Geo., 



vol. 6, Calciferous Gr. 

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



p. 321, Quebec Gr. 



AMPHIPELTIS, Salter, 1863, Qnar. Jour. Geo. 

 Soc., vol. 19, p. 75. 

 [Ety. amphi, on both 

 sides ; peltis, provided 

 with a shield or buck- 

 ler.] Carapace oblong, 

 oval, rounded in front, 

 more truncate behind ; 

 thorax with 9 seg- 

 ments, 5 project be- 

 yond the carapace and 

 4 concealed beneath 

 it' ; tail-piece semi- 

 circular, as wide as 

 the abdomen, and as 

 long as the last three 

 segments taken to- 

 gether. Type A. para- 

 doxus 

 peltis paradoius. paradoxu8) Salter, 1863, 



Quar. Jour. Geo. Soc., vol. 19, p. 76, 

 and Acad. Geo., p. 523, Up. Devonian. 

 AMPYX, Dalman, 1827, Uber die palseaden 

 oder die sogenannten Trilobiten, p. 53. 

 [Ety. ampyx, head-band.] Cephalic 

 shield somewhat trigonal ; glabella large, 

 prominent, narrow behind, and pro- 

 Acting upward and forward anteriorly ; 

 cheeks flattened, posterior angles pro- 

 duced ; no eyes or facial sutures ; 

 thoracic segments 5 or 6, flattened, 

 sides straight, divided by a diagonal 

 pleural groove ; pygidium 

 subtrigonal, nearly as large 

 as the cephalic shield ; one 

 anterior segmental furrow; 

 axis faintly marked with 

 transverse furrows. Type 

 A. nasutus. 



halli, Billings, 1861, Pal. Foss., 

 vol. 1, p. 24, Chazy Gr. 



Iseviusculus, Billings, 1865, 



Pal. Foss., vol. 1, p. 295, FIG. 958. - 

 Quebec Gr. Ampyx 



normalis, Billings, 1865, Pal. Hea^'wUh- 

 Foss., vol. 1, p. 295, Que- out mov- 

 bec Gr. ablecheeks 



rutilius, Billings, 1865, Pal. f,vg ldlu ^ e 

 Foss., vol.1, p. 296, Quebec Gr. 



semicostatus, Billings, 1865, Pal. Foss., 

 vol. 1, p. 297, Quebec Gr. 



FIG. 957. Amphi- 



FIG. 959. Anopole- 

 nus vemistus. 



Angelina kitchcocki, see Prototypus hitch- 



cocki. 



Anomocare, Angelin, 1852, Pal. Scand., p. 

 24. This genus is not yet known in 

 America. 



(?) part-urn, Walcott, 1885, Mon. U. S. Geo. 

 Sur., vol. 8, p. 59, Up. Taconic. This 

 species is founded on a fragment of the 

 cephalic shield and the generic refer- 

 ence is only provisional. 

 ANOPOLESUS, Salter, 1864, Quar. Jour. Geo. 

 Soc., vol. 20, p. 236, and vol. 21, p. 477. 

 [Ety. a, without; ops, an eye; Olenus, 

 atjenus.] Elongated, depressed ; cephalic 

 shield semicircular with prolonged 

 spines, and clavate glabella having 4 

 pairs of furrows; fixed cheeks, large, 

 punctate, strongly margined, each a 

 quarter of a circle in shape, and reach- 

 ing nearly to the front of the glabella, 

 against which the long eyes abut; 

 thence the facial suture curves out- 

 ward, and is marginal 

 in front; the long eye- 

 lobe, which forms the 

 margin of the fixed 

 cheeks, reaches quite 

 to the glabella in 

 front, and nearly to 

 the posterior angle 

 below ; free cheeks 

 are a narrow band 

 margined and reaching only three- 

 fourths down the fixed cheek ; pygid- 

 ium wide, expanded, but narrower 

 than the thorax, widely marginate, 

 and serrated by 6 or 8 marginal spines. 

 Type A. henrici. 

 venustus, Billings, 1874, Pal. Foss., vol. 2, 



p. 73, Up. Taconic. 

 ANTHR ACONKCTES, 

 Meek & Worthen, 

 1868, Am. Jour. 

 Sci., vol. 46, p. 

 21, and Geo. Sur. 

 111., vol. 3, p. 544. 

 [Ety. anthrax, 

 coal ; nectos, swim- 

 ming.] Dis- 

 tinguished from 

 Eurypterus by the 

 absence of lateral 

 spines nt the ar- 

 ticulations of the 

 legs, which ter- 

 minate in single FIG. 9GO.-Anthraconec- 

 nmnts nnrl in tho tes Hiflzonensis. Hy- 

 points, ana mine postoitm enlarged to 

 great length and 

 simple extremity 

 of the mesial ap- 

 pendage of its operculum, as well as 

 in the possession of two little spatu- 

 late supplementary pieces. Type A. 

 mazoneusis. 



mazonensis, Meek & Worthen, 1868, Am. 

 Jour. Sci and Arts, vol. 46, p. 21, and 

 Geo. Sur. 111., vol. 3, p. 544, Coal 

 Meas. 



show the scale-like 

 sculpturing. 



