526 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxii. 



Icon., XVI, 164, pi. II, fig. 7.— *B H. Wright, Check List, 1888.— ^ P^tel, 



Conch. Sam., Ill, 1890, p. 147. 

 "" Margarita (Unio) ccelatus Lea, Syn., 1836, p. 12; 1838, p. 14. 

 * Margaron ( Unio) ccdatus Lp:a, Syn., 1852, p. 20; 1870, p. 20. 



Tennessee River drainage; cited from Michigan by Sager and Miles, 

 certainly in error. They might have mistaken for this a rather high 

 specimen offahalis. 



Genus LAMPSILIS Rafinesque, 1820. 



(Type, Unio ovatiis Say.) 



Lanipsilis Eafinesque, Ann. Gen. Sci. Phys. Brux., 1820, p. 298. 



Shell oval to elliptical, smooth or slightly concentrically sculptured, 

 usually without a posterior ritlge; epidermis generally smooth and shin- 

 ing, often brilliantly rayed; beak sculpture, for the most part, consist- 

 ing of fine, parallel ridges, which show a tendency to fall into an ante- 

 rior and posterior loop; hinge with one or two pseudocardinals and 

 one lateral in the right valve, and two pseudocardinals and two lat- 

 erals in the left; female shell having a moderate and gradual inflation 

 in the post- ventral region opposite the marsupium. Animal with the 

 inner gills usually attached nearly or quite their entire length to the 

 abdominal sac; marsupium occupying the hinder part of the outer gills; 

 ovisacs distinct, separated by sulci, rounded below, having a fold near 

 their bases, the whole projecting below the inner gills; mantle edge 

 double and thickened, often swollen behind into a sort of flap in the 

 female. 



Section LAMPSILIS Rafinesque. 

 (Type, Unio oratus Say.) 



Shell inflated, rather thin, shining, sometimes having a posterior 

 ridge; beak sculpture coarse, consisting of a few, more or less, parallel 

 ridges, which scarcely fall into loops. Animal having the mantle of the 

 female usually toothed and thickened on the post basal portion, which 

 develops into a large, curious flap when the gills are filled with ova. 



- tLAMfSILIS VENTRICOSUS Barnes. 



* Unio rentricosHS Barnks, Am. Jl. Sci., VI, 1823, p. 267, pL xiii, fig. 14 (outline).— 



*Say, Am. Conch., No. IV, 1832, pi. xxxii.— Terussac, Guer. Mag., 1835, p. 

 26.— *C. B. Adams, Thompson's History of Vermont, 1842, p. 167; F. W. 

 auclL. S. of Vermont, 1842, p. 17.— *Hanley, Test. Moll., 1842, p. 189; * Biv. 

 Shells, 1843, p. 189, pi. xxiv, fig. 8.—* De Kay, Zool. of N. Y., Pt. 6, 1843, p. 

 190.— *Chenu, Bib. Couch., 1st ser. Ill, 1845, p. 45, pi. xii, figs. 1, 2.— *H. 

 and A. Adams, Gen. Rec. Moll., II, 1857, pp. 492, 495.—" Sowerby, Couch. Icon., 

 XVI, 1866, pi. XLiii, fig. 235.—^ B. H. Wright, Check List, 1888. 



* Mya ventricosits Eaton, Zool. Text-Book, 1826, p. 221. 



* Margarita ( Unio) ventricosiis Lea, Syn., 1836, p. 23; 1838, p. 18. 



* Margaron ( Unio) rentricosiis Lea, Syn., 1852, p. 26; 1870, p. 41. 



* Lampsilis ventricosus Baker, Moll. Chicago, Pt. 1, 1898, p. 94, pi. xii, figs. 3-5. — 



^ Smith, Bull. U. S. Fish Com., 1899, p. 291, pi. Lxxxin. 



