SYNOPSIS 



GENERUM ET SPECIERUM GRAVIGRADUUM Q,VJE IN HOC OPERE DESCRIBUNTUR ET INDICANTUR. 



Fam. GEAVIGRADA. 



Pedes breves, fortissimi, tequales aut subsequales : manibus penta-vel tetradactylis, pedibus 

 penta-? vel tetra-vel tridactylis ; digitis externis 1 aut 2, muticis, ad sufifaltionem gressumque 

 idoneis, reliquis falculatis. 



Arcus zygomaticus clausus. Claviculas perfectas. Cauda mediocris, crassa, fulciens. — Owen. 



MEGALONYX, Jefferson. 



Deates discreti ; antici e reliquis remoti, magui, elliptic! ; reliqui superiores trigoni, 



4 — 4 

 inferiores tetragoni. Pedes asquales: manibus et pedibus? pentadactylis. Falculse magnse, 

 compressEe. Femur capite integro. Tibia et fibula discretse. 



1. Megalonyx Jefffersonii, Harlan. — Dentes magni antici latfe elliptici; superiores 



ultimi trigoni. Hab. America septentrionalis. — Virginia, Kentucliy, Tennessee, 

 Mississippi, Alabama. 



Meffalonyx, Jefferson, Trans. Am. Phil. Soc. IV, 1*799, 246.— Wistak, Ibid. 526, 



Pis. 1, ii. — CuviER, Ann. du Mus. V, 1804, 358, PI. xxxin,fffura; omnes, Fig. 



13? excepta.—lB. Ossem. Foss. Ed. 4, VIII, 1836, 304, PI. ccxvi, Fig. 13? 



excepta. — Cooper, Aim. Lye. Nat. Hist. Ill, 1836, 166. 

 Megatherium Jeffersonii, Desmarest, Mammalogie, 1820, 366. 

 Megahmjx Jeffersonii, Harlan, Faun. Amer. 1825, 201. — Ib. Med. and Phys. Res. 



1835, 271. 

 Megalonyx laqueatus, Harlan, Journ. Ac. Nat. Sc. Pli. VI, 1830, 269, Pis. xii-xiv. 



— Ib. Med. and Phys. Res. 1835, 213; Ib. 319, Pis. xii-xiv, et xv. Fig. 5-7.— 



Wyman, Am. Journ. Sc. and Arts, X, 1850, 58, Fig. 1, 2.— Leidy, Proc. Ac. 



Nat. Sc. Ph. VI, 1852, 117. 

 Aulaxadon seu Pleurodon, Harlan, Journ. Ac. Nat. Sc. Ph. VI, 1830, 284. — Ib. 



Med. and Phys. Res. 1835, 330. 

 Megatherium horeale, Oken. 

 Onychotherium, FisCHER. 

 Megalonyx potens, Leidy, Proc. Ac. Nat. Sc. Ph. VI, 1852, 117. 



2. Megalonyx dissimilis, Leidy. — Dentes magni antici august^ elliptici ; superiores 



ultimi vix trigoni sed potius elliptici. Hab. America septentrionalis. — Mississippi. 

 Megalonyx dissimilis, Leidy, Proc. Ac. Nat. Sc. Ph. VI, 1852, 117. — Ib. Ancient 

 Fauna of Nebraska, 9. 



