540 PROCEEDINGS OF THE NATIONAL MUSEUM. 



tLAMPSILIS LIGAMENTINUS var. GIBBUS Simpson, i 



* Unio crassus Sowkrby, Concli. Icon., XVI, 1868, pi. xcv, fig. 520. 



Mississippi River drainage generally; southern Michigan; western 

 New York; Manitoba; Ontario; the variety from the Ohio River 

 southward. 



tLAMPSILIS ORBICULATUS Hildreth. 



* Unioorbiculatus Hildreth, Am. Jl. Sci., XIV, 1828, p. 284.— ''HANLEY,Test. Moll., 



1842, p. 192; Biv. Shells, 1843, p. 192, pi. xxi, fig. 2.— ^Catlow aiuT Reeve, 

 Conch. Norn., 1845, p. 62.— *Conrad, Pr. Ac. N. Sci., Phila., VI, 1853, p. 254.— 

 *H. and A. Adams, Gen. Eec. Moll., II, 1857, p. 494. — *Kuster, Conch. Cab., 

 1861, p. 216, pi. Lxxi, figs. 3, 4.— *SowERBy, Conch. Icon., XVI, 1866, pi. 

 XLiv, fig. 239.— *Calkins, Pr. Ottawa Ac. Sci., 1874, p. 44.— *B. H. Wright, 

 Checlt List, 1888.— *P.etel, Conch. Sam., Ill, 1890, p. 162. 



* MargarifM {Unio) orMoidatus 1j¥^\, Syn., 1836, p. 25; 1838, p. 19. 



* Margaron ( Unio) oriiculatus Lea, Syn., 1852, p. 28; 1870, p. 43. 



* Unio ahruptus Say, Am. Couch., No. II, 1831, pi. xvii.— *Conrad, New F. W. 



Shells, 1834, p. 67.— *Chenu, Bib. Conch., 1st ser., Ill, 1845, p. 24, pi. vi, figs. 

 1, Irt, lb. — ''Desha YES, An. sans Vert., 2cl ed., VI, 1835, p. 555;* 3d ed., II, 

 1839, p. 674. 

 •* Unio cyclips Ferussac, Guer. Mag., 1835, p. 28. 



* Unio crassus Conrad, Monog., IV, 1836, p. 34, pi. xvi. 



Ohio and Cumberland rivers; west to the Mississippi River; north 

 to Minnesota. Some specimens can hardly be separated from L. 

 higginsii. 



tLAMPSILIS HIGGINSII Lea.^ 



* Unio higginsli Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 84; * Jl. Ac. N. Sci. Phila., 



V, 1862, p. 188, pi. XXIV, fig. 258; *Obs., IX, 1863, p. 10, pi. xxiv, fig. 258.— 

 *SowERBY, Conch. Icon., XVI, 1868, pi. lxxxii, fig. 431.— *B. H. Wright, 

 Check List, 1888.— 'P^etel, Conch. Sam., Ill, 1890, p. 155. 



* Margaron (Unto) higginsii Lea, Syn., !870, p. 41. 



Ohio River, west to Iowa, and southwest to Kansas. 



tLAMPSILIS PINGUIS Lea.' 



UrAo jnngiiis Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. 84; ML Ac. N. Sci. Phila., IV, 

 1858, p. 78, pi. XV, fig. 58; *Obs., VI, 1858, p. 78, pi. xv, fig. 58,— *B. H. 

 Wright, Check List, 1888. 



* Margaron ( Unio) iringivis Lea, Syn., 1870, p. 44. 



St. Peters River, Minnesota. Doubtful. 



^A peculiarly humped form of Ugamentinus, common throughout the southern 

 range of the species, may bear the above name. 



'^A somewhat puzzling species, of which male specimens often approach closely to 

 Ohovaria ellipsis in form, but the pseudo cardinals are always stumpy and never longi- 

 tudinal, as they generally are in that genus. It is probably an aberrant form, 

 closely related to X. orhiculatus. The females are more inflated in the postbasal region 

 than in any other member of the group. 



■'I have seen only one specimen of this, the type, which is an exceedingly puzzling- 

 form. The hinge line is injured and curves in strongly in front of the beaks, where 

 there is a large, irregular limule. and the pseudoeardiuals are compressed. It may 

 be a young, diseased orhiculatus. 



