CLASS BKACHIOPODA. 



FAMILY CALCEOLID^.— Calceola. 



FAMILY CRANIIDiE. — Crania, Pholidops, Pseudocrania, Schizocrania. 



FAMILY DISCINID^.— Discina, Trematis. 



FAMILY KONINCKIIDiE.— Koninckia. 



FAMILY LINGULIDvE.— Kutorgina, Leptobolus, Lingula, Lingulella, Lingulepis, Lin- 



gulops, Obolus, Obolella. 

 FAMILY ORBICULID^.— Acrotreta, Iphidea, Orbicula. 

 FAMILY ORTHID^.— ^gilops, Meekella, Orthis, Orthisina, Skenidium, Tropidoleptus, 



Vitulina. 

 FAMILY PENTAMERID^.—Amphigenia, Anastrophia, Camarella, Camarophoria, 



Gypidiila, Pentamerella, Pentamerus, Stricklandinia. 

 FAMILY PORAMBONITID^.— Porambonites. 



FAMILY PRODUCTIDvE.— Aulosteges, Chonetes, Productella, Productus, Strophalosia. 

 FAMILY RHYNCHONELLID^.— Acambona, Eatonia, Leiorhynchus, Rhynchonella, 



' Stenoschisma. 

 FAMILY SPIRIFERID^. — Amboccelia, Athyris, Atrypa, Camarium, Cryptonella, 



Cyrtia, Cyrtina, Eichwaldia, Martinia, Merista, Meristella, Meristina, Nucleospira, 



Pentagonia, Retzia, Rhynchospira, Spirifera, Spiriferina, Syntrielasma, Syringo- 



thyris, Trematospira, Trigonotreta, Waldheimia, Zygospira. 

 FAMILY STROPHOMENID^.— Leptaena, Streptorhynchus, Strophodonta, Stro- 



phomena. 

 FAMILY TEREBRATULID^. — Centronella, Coelospira, Leptocrelia, Rensselseria, 



Terebratula. 

 FAMILY TRIMERELLID^:— Dinobolus, Monomerella, Trimerella. 



AcAMBONA, White, 1862, Proc. Bost. Soc. 



Nat. Hist., voL 9. [Ety. aka, a point ; 



umbona, umbo.] 

 prima, White, 1862, Proc. Bost. Soc. Nat, 



Hist., vol. 9, Burlington Gr. [Sig. first.] 

 AcROTRETA, Kutorga, 1848, Uber die Siphon- 



otretse aus den Verhandlungen der 



Kaiserlichen Mineralogischen Gesell- 



scaft fur Jahr. [Ety. akros, the top or 



summit; tretos, perforated.] 

 attenuata, Meek, 1872, Hayden's Geo. 



Rep., Potsdam Gr. [Sig. drawn out.] 

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



Quebec Gr. [Sig. a young bud.] 

 pyxidicula, White, 1874, Rep. Invert. 



Foss., Quebec Gr. [Sig. a little box.] 

 subsidua, White, 1874, Rep. Invert. Foss., 



Potsdam Gr. [Sig. sinking down.] 

 ^GiLOPs, Hall, 1850, 3rd Reg. Rep. [Ety. 



fegilops, an acorn.] 

 Bubcarinata, Hall, 1850, 3rd Reg. Rep., 



Trenton Gr. [Sig. somewhat keeled.] 



AMBOCffiLiA, Hall, 1860, 13th Reg. Rep. 

 [Ety. ambon, umbo; koUos, the belly.] 



gemymda, syn. for Spirifera planoconvexa. 



gregaria, see Ambocoelia umbonata var. 

 gregaria. 



minuta, White, 1862, Proc. Bost. Soc. 

 Nat. Hist., vol. 9, Chemung Gr. [Sig. 

 very small.] 



nucletJLS, syn. for Ambocoelia umbonata. 



prseumbona. Hall, 1857, (Orthis praeum- 

 bona) 10th Reg. Rep., Ham. Gr. [Sig. 

 very protuberant.] 



suhumbona, see Spirifera, subumbona. 



umbonata, • Conrad, 1842, (Orthis umbo- 

 nata) Jour. Acad. Nat. Sci., vol. 8, 

 Marcellus shale & Ham. Gr. [Sig. 

 protuberant, bossed.] 



umbonata var. gregaria, Hall, 1860, (Am- 

 bocoelia gregaria) 13th Reg. Rep., 

 Chemung Gr. [Sig. in a common 

 flock.] 



