NO. 1205. SYNOPSIS OF THE XJ lAUFS-^lMPSOy. 667 



what radiatel^' ridged ; laterals short, very imperfect, or wanting; beak 

 cavities deep, compressed. 



Animal with inner gills wider than the outer throughout; palpi long; 

 marsupium loose and flabby, and having ova scattered throughout it 

 in the only gravid specimen seen. 



t ALASMIDONTA UNDULATA Say. 



Monodonia uiuhilaia Say, Nich. Enc; 1816, pi. iii, fig. 3. 



"" Alasmidonta undiilafa Say, Jl. Acad. N. Sci. Phila., 1, 1818, p. 460. 



"" Alasmodonta undulata Say, Nich. Enc, IV, 1819, pi. in, fig. 3.—* Conrad, New 



F. W. Shells, 1834, p. 73.— "* Fercssac, Guar, Mag., 1835, p. 26.— ^C. B. 



Adams, F. W. and L. S. of Vt., 1842, p. 15. 

 "-Alasmodon undulata Swainsox, Tr. on Mai., 1840, p. 288, fig. 61.— * Gould, Inv. 



Mass., 1841, p. 115, fig. 76.— *Dfc: Kay, Zool. of N. Y., Pt. 5, 1843, p. 198, pi. xv, 



fig. 227. 

 "'Marrjarila (Margaritana) undulata Lea, Syn., 1836, p. 44; 1838, p. 27. 

 ^ Unio undulata Haxley, Test. Moll., 1842, p. 211.—* Bi^^ Shells, 1843, p. 211. 

 "" Margaritana undulata KtiSTER, Conch. Cab. Unio, 1862, p. 298, pi. xcix, fig. 4. — 



* Gould, Inv, Mass., 1870, p. 176, fig. 478.—* Hartman and Michener, Conch. 



Cest., 1874, p. 92, fig. 190.— ^Latchford, Tr. Ottawa F. N. CI., 1882, p. 



54.— *H. Carpenter, Naut., IV, 1890, p. 47.— *B. H.Wright, Check List, 



1888.—* P.ETEL, Conch. Sam., Ill, 1890, p. 174. 

 ^Margaron (Margaritana) undulata Lea, Syn., 1852, p. 42; 1870, p. 68. 

 "Mya undulata Wood, Ind. Test. Eev., 1856, p. 199, pi. i, snpp., fig. 5. 

 ""Banliia undulata H. and A. Adams, Geu. Rec. Moll., II, 1857, p. 499. 



* Unio undulatus Catlow and Reeve, Conch. Nom., 1845, p. 65. 

 ""Strophitus undulatus Stimpson, Shells of New Eng., 1851, p. 15. 

 *?rH(o glabratus Sowerby, Rec. and Foss. Shells, XVI, 1823, fig. 

 Alasmodonfa sculptiUs Say, N. Harmony Diss., II, 1829, p. 339.— Ferussac, Guer. 



Mag., 1835, p. 26.— L. W. Say, Terr, and Fluv. Shells, 1840, p. 9. 

 "Stropliitus aculjHilis Stimpson, Shells of New Eng., 1851, p. 15. 



* Unio hians Valexciennes Rec. Obs. Zool , II, 1833, p. 235, pi. liv, figs. 2a, 2?). 



* Uniopsis radiata Swainsox, Tr. on Mai., 1840, p. 289, fig. 62. 



* Uniojisis mytiloides SwAixsoN, Tr. on Mai., 1840, p. 382, fig. 62. 

 "lUnio swainsoni Sowerby, Conch. Icon., XVI, 1868, pi. lxxvi, fig. 396. 

 ^Margaron {Margaritana) swainsoni Lea, Syn., 1870, p. 30. 



Lower St. Lawrence drainage; southward to North Carolina. 



Subgenus PEESSODONIA Simpson, 1900. 

 (Type, Unio calceolus Lea. ') 



Shell decidedly rhomboid, surface generally painted with unbroken 

 rays; beak sculpture slightly corrugated; teeth compressed. 

 Animal with a thick, smooth, pad like marsupium. 



(Group of Alasmidonta caJceola.) 



Shell small, subsolid, rhomboid, inflated, rayed but not shining; 

 beak sculpture varying from strong concentric bars to irregular corru- 

 gations, sometimes faintly doubly looped, and with fine radiating 



'The names Hemiodon, Hemiodonta, and Hemidon were applied by Swamson to 

 this group, but he used the first name jjreviously for a division of the Helicidse. It 

 is better to apply a new name. 



