354 



BRACHIOPODA. 



[mKR— MON. 



recurving upon themselves, are re- 

 united laterally. Type M. lrevis. 



arcuata, Hall, 1857, 

 ( Merista arcuata, ) 



^.. s 



Fig. 582. — Meristella 

 clrce. Showing re- 

 mains of spiral ap- 

 pendages in the 

 dorsal valve. 



10th Rep. N. Y. St. 



Mus. Nat. Hist., p. 



w« 95, and Pal. N. V.. 



\\ WH TW M vol. 3, p. 249, Low. 



Held. Gr. 



barrisi, Hall, 1860, 



13th Rep. N. Y. St. 



Mus. Nat. Hist., p. 



84, and Pal. N. Y., 



vol. 4, p. 304, Mar- 



cellus shale and 



Ham. Gr. 



circe, Billings, 1861, 



(Cnarionella circe,) 



Can. Jour., vol. 6, 



p. 273, Up. Held. 



(Jr. 



cylindrica, Hall, 1852, (Atrypa cylin- 

 drical Pal. N. Y., vol. 2, p. 76, Clinton 

 and Niagara Gr. 

 doris, 1860, Hall, 13th Rep. N. Y. St. 

 Mus. Nat. Hist., p. 84, and Pal. N. Y., 

 vol. 4, p. 303, Schoharie grit and Cor- 

 niferous Gr. 

 elma, syn. for Meristella nasuta. 

 haskinsi, Hall, 1860, 13th Rep. N. Y. 8t 

 Mus. Nat. Hist., p. 84, and Pal. N. Y., 

 vol. 4, p. 306, Ham. Gr. 

 (?) hyale, Billings, 1862, (Charionella 

 (?) hyale,) Pal. Fobs., vol. 1, p. 16«, 

 Guelph (Jr. 

 julia, Billings, 1862, (Athyris julia,) Pal. 



Foss., vol. 1, p. 146, Mid. Sil. 



lsevis, Vanuxem, 1843, (Atrypa hevis,) 



Geo. Rep. 3d Dist. N. Y., ]i. 120, and 



Pal. N. Y., vol. 3, p. 247, Low Held. < ir. 



lenta, Hall, 1867, Pal. N. Y., vol. 4, p. 490, 



Oriskany sandstone. 

 maria, see Whitfieldia maria. 

 meta, Hall, 1867, Pal. N. Y., vol. 4, p. 308, 



Ham. Gr. 

 nasuta, Conrad, 1840, (Atrypa nasuta,) 

 Ann. Rep. N. Y., p. is. and I'al. N. Y., 

 vol. 4, p. 299, Schoharie grit, Dp. Held. 

 and Ham. ( ir. 

 princeps, Hall, 1857, (Merista princeps,) 

 10th Rep. N. Y. St. Mus. Nat. Hist., p. 

 96, and Pal. N. Y., vol. 3, p. 252, Low. 

 Held. Gr. 

 prinstana, Billings, 1862, (Athyris prins- 

 tana,) Pal. Foss., vol. 1, p. 145, Mid. Sil. 

 rectirostra, Hall, 1879, Desc. New Spec. 

 Foss., p. 15, and 11th Rep. Geo. and 

 Nat. Hist. Ind., p. 301, Niagara Gr. 

 rostrata, Hall,1843,(Atrypa 

 rostrata,) Geo. Rep. 4th 

 Dist. N. Y., p. 202, and 

 Pal. N. Y., vol. 4, p. 307, 

 Ham. (Jr. and Tully 

 limestone. 



scitula, Hall, 1843, (Atrypa Fl t ^uf r^SS 

 scitula,) Geo. 4th Dist. Side view. 

 N. Y., p. 171, and Pal. 

 N.Y., vol. 4, p. 302, Corniferous Gr. Hall 

 regards M. circe as a syn. for this species. 



unisulcata, Conrad, 1841, (Atrypa uni- 

 sulcata,) Ann. Rep. N. Y., p. 56, and 

 Pal. N. Y., vol. 4, p. 309, Up. Held, and 

 Hani. (Jr. 

 Mkristina, Hall, 1867, 20th Rep. N. Y. 8t. 

 Mus. Nat. Hist, p. 186, and Pal. N. Y., 

 vol. 4, p. 299. [Ety. Merista, a genus ; 

 inut, implying resemblance.] General 

 form like Meristella ; apex perforated ; 

 lamella; of the spires united by a sim- 

 ple loop ; spirals oval, and each con- 

 tains about nine convolutions ; the 

 two principal stems attach to the hinge 

 plate and extend into the interior be- 

 tween the spirals, where they bend 

 backward and give forth converging 

 lamella", which cross between the spirals 

 to the ventral side, where they unite in 

 an angular point. Type M. nitida. 



nitida, Hall, 1843, 

 (Atrypa nitida,) 

 ( Jeo. Rep. 4th 

 Dist. N. Y., pi. 14, 

 and Pal. N. Y, vol. 

 2. p. 268, Niagara 

 (Jr. 



nitida var. oblata, 

 Hall, 1852, (Atrypa 

 nitida var. oblata, i Kl ,, lS |. ftferistlna 



Pal. N. Y., VOl. L', p. nitida Dorsal 



269, Niagara (ir. vlew - 



Monmmkici i i \, Billings, 1871, Can. Nat. and 

 I too., vol. 6, p. 220. [Ety. mono*, OM ; 

 imriis, a part; ella, diminutive termina- 

 tion.] Shell thick, circular or trans- 

 versely oval in its marginal outline; 

 umbo of the pedicle, valve large, pro- 

 jecting, double-chambered; area and 

 deltidlum large; hinge thick, elevated, 

 led<^e-shaped, concave in the middle 

 portion ; cardinal facet a wall-like 

 space behind the ledge or Hat of the 

 binge; cardinal buttress strong, la- 

 melTiform ; platform flat, slightly ele- 

 vated, widest, highest, and obtusely 

 angulated in front; umbo of the 

 brachial valve rounded; hinge moder- 

 ately thick ; platform trilobed ; usually 

 with a thin margin. Type M. prisca., 

 newberry i , 

 Hall & 

 Whitfield, 

 1875,Ohio, 

 l'al., vol. 



2, P . i:;i, 



Niagara 

 (ir. 

 orbicular! i , 

 Bill in gf , 

 1871, Can. 

 Nat., vol. 

 (», p. 220, 

 Guelph Gr. 

 Foss., vol. 



Fig. 585.— Monomerella prisca. 



ovata, Whiteaves, 1884, Pal 



3, p. 5, Guelph Gr. 

 ovata var. lata, Whiteaves, 1884, Pal. 



Foss., vol. 3, p. 6, Guelph Gr. 

 prisca, Billings, 1871, Can. Nat. and Geol., 



vol. 6, p. 220, Guelph Gr. 



