532 



CRUSTACEA. 



[ATO. BAT. 



wetherilli, Green, syn. for Dalmanites lim- 



ulurus. 



wisconsinensis, Walcott, 1876, 28th Rep. 

 N. Y. Mus. Nat. Hist., p. 97, Trenton Gr. 

 ATOPS, Emmons, 1844, Taconic System, p. 

 64, and Am. Geol. p. 115. [Ety. a, ab- 

 sence of ; ops, an eye.] Cephalic shield 

 semicircular, anterior and lateral edges 

 turned upward,posterioranglesrounded, 

 convex ; glabella subquadrate, convex, 

 appearing as a continuation of the cen- 

 tral lobe, two lateral furrows on each 

 side, neck segment well defined ; facial 

 suture beginning at the antero-lateral 

 part of the cephalic shield, runs nearly 

 parallel with the anterior margin to the 

 front of the glabella, when it turns at 

 right angles and runs parallel with the 

 glabella to the posterior margin; no 

 eyes ; thoracic segments 17, axial nearly 

 as wide as the lateral lobes, narrowing 

 gradually to the pygidium, armed with 

 a row of short spines, lateral lobes with 

 a row of tubercles on the median line ; 

 pygidium small, somewhat semiellip- 

 tical, flat, axial lobe with a single ring. 

 Type A. trilineatus. 



fischeri, Billings, 1865, (Triarthrus fisch- 

 eri,) Pal. Foss., vol. 1, p. 291, Quebec 

 Gr. or Up. Taconic. 



miser, Billings, 1861, (Conocephalites mi- 

 ser,) Pal. FOBS., vol. 1, p. 12, Up. Ta- 

 conic. 



trilineatus, Emmons, 1844, Taconic Sys- 

 tem, p. 64, and Am. Geol., p. 115, Up. 

 Taconic. 



BAILIELLA, Matthew, 1884, Trans. Roy. Soc. 

 Can., vol. 2, 

 pi. 1. [Ety. 

 proper name.] 

 Proposed as a 

 subgenus and 

 founded on 

 Conocoryp h e 

 baileyi. 



BARRANDIA. Mc- 

 Coy,1849,Ann. 

 Nat. Hist, 2d 

 ser. vol. 4, p. 

 409. [Ety. 

 proper name.] 

 Ovate, de- 

 pressed ; g 1 a - 

 bella with in- 

 completeaxial 

 furrows and 

 no distinct 

 lobes ; eyes 



FIG. 96-Atops trilineatus. central ; facial 



suture cutting the posterior margin 

 about the middle, and in front of the 

 eyes arching forward, first outward and 

 then inward ; pleurte falcate, with a 

 fulcrum close to the axis, grooved, not 

 faceted ; pygidium with short axis and 

 smoottrsides. Type B. cordai. 

 (?) maccoyi, Walcott, 1885, Monogr. U. S. 

 Geo. Sur., vol. 8, p. 96, Trenton Gr. 



Barrandia, Hall, 1860. The name was pre- 

 occupied by McCoy in 1849 ; beside, it is 

 a syn. for Elliptocephala. 

 thompsoni, see Elliptocephala thompsoni. 

 vermontana, see Eiliptocephala vermont- 

 ana. 



BATHYNOTUS, Hall, 1860, 3d Rep. N. Y. St. 

 Mus. Nat, Hist., p. 117. LEty. bathys, 

 ample; notos, back.] Cephalic shield 

 somewhat semielliptical, with posterior 



FIG. 970 Bathynotus holopyga. Long eye-lobes 

 crushed down. 



angles produced in very long spines; 

 glabella transversely lobed ; eye-lobe 

 narrow, elongate, extending from op- 

 posite the antero lateral angle of the 

 glabella obliquely backward nearly to 

 the posterior margin ; facial suture 

 passes nearly around the extended eye- 

 lobe, and cuts the margin before reach- 

 ing the posterior extension of the eye- 

 lobe ; anteriorly it passes in front of the 

 glabella without, as it appears, cutting, 

 the front margin ; free cheeks united in 

 front; thirteen thoracic segments; mid- 

 dle lobe prominent, twice as wide as 

 the lateral lobes; articulations strong, 

 each bearing a cenlral node ; pleurae 

 short, each terminating in a spine, the 

 last pair being prolonged far beyond 

 the pygidium ; pygidium short, middle 

 lobe with three annulations, lateral 

 lobes flat and plain ; hypostoma hav- 

 ing an obtuse angle; at the front mar- 

 gin of the doublure, the latter being 

 cut away to permit the extension to 

 cross it, behind the doublure it is trans- 

 versely quadrangular. Type B. holo- 

 pyga. 



holopyga, Hall, 1859, (Peltura holopyga,) 

 12th Rep. N. Y. St. Mus. Nat. Hist., 

 p. 61 and Pal. N. Y., vol. 3, p. 528, Up. 

 Taconic. 



