592 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XXII. 



for all or part of their length ; mantle thickened on the edge, which is 

 often dark colored; anal and branchial openings large and well fur- 

 nished with papilla. Nothing is known of the marsupiuin of any mem- 

 bers of this group, the animals examined probably being males; but it 

 is most likely that when gravid the ovules will be found in distinctly 

 marked ovisacs in the posterior part of the outer gills, something as 

 in Lampsilis. 



(Group of Nephronaias medellinus.) 



Shell scarcely sulcate, shining, rather brightly rayed, distinctly bian- 

 gulate behind, solid, swollen; beaks rather full, with delicate sculpture; 

 pseudocardiuals solid, stumpy, trigonal; laterals heavy, somewhat club- 

 shaped; nacre rich and soft, silvery or purple; female shell consider- 

 ably inflated at the post- basal region, and differing somewhat from that 

 of the male. 



t NEPHRONAIAS MEDELLINUS Lea. 



f Unio purpuriatus SAY, New Harmony, Diss. (newspaper form), January 15, 1831. ' 



* Unio medellinus LEA, Tr. Am. Phil. Soc., VI, 1838, p. 39, pi. xn, fig. 34 ; * Obs., II, 



1838, p. 39, pi. xn, fig. 34. * TROSCHKL, Arch, fur Naourg., V, 1839, Pt.2, p. 

 236. *HAXLEY, Test. Moll, 1842, p. 193; *Biv. Shells, 1843, p. 193, pi. xxi, 

 fig. 19; pi. xxin, fig. 8. *CATLO\V and REEVE, Conch. Nom., 1845, p. 61. 

 *CHENU, 111. Conch., 1858, pi. xvn, figs. 6, 6a, 6Z>. *H. and A. ADAMS, 

 Gen. Rec. Moll., II, 1857, p. 494. * KUSTER, Conch. Cab., 1861, p. 162, pi. 

 XLVI, fig. 5. *SOWERBY, Conch. Icon., XVI, 1866, pi. xxxni, fig. 171. * B. 

 H. WRIGHT, Check List, 1888. *P,ETEL, Conch. Sam., Ill, 1890, p. 158. 

 * P'lsCHER and CROSSE, Miss. Sci., Pt. 7, II, 1894, p. 603. 



* Margarita ( Unio) medtlUnus, LEA, Syn., 1836, p. 26; 1838, p. 19. 



* Maryaron (Unio) medrllinus, LEA, Syn., 1852, p. 29; 1870, p. 45. 



t*Cnio strebeli, LEA,- Pr. Ac. N. Sci. Phila., X, 1866, p. 133; *J1. Ac. N. Sci. 

 Phila., VI, 1868, p. 318, pi. LI, fig. 131 ; * Obs., XII, 1869, p. 78, pi. LI, fig. 131. 

 *B. H. WRIGHT, Check List, 1888. * FISCHER and CROSSE, Miss. Sci., Pt. 7, 

 II, 1894, p. 595. 



*Margaron ( Unio) Strebeli, LEA, Syn.. 1870, p. 53. 



State of Vera Cruz, Mexico. 



t NEPHRONAIAS SAPOTALENSIS Lea. 



* UniosapotalensesLKAj'PT. Am. Phil. Soc., II, 1841, p. 30; * Tr. Am. Phil. Soc., VIII, 



1842, p. 233, pi. xxi, fig. 47; * Obs., Ill, 1842, p. 71, pi. xxi, fig. 47.* CONRAD, 

 Pr. Ac. N. Sci. Phila., VI, 1853, p. 257. *H. and A. ADAMS, Gen. Rec. Moll., 

 II, 1857, p. 494. *CHENU, 111. Conch., 1858, pi. xxxni, figs. 4, 4a, 4&. *Sow- 

 ERBY, Conch. Icon., XVI, 1868, pi. XLI, fig. 495. * B. H. WRIGHT, Check List, 



1 Believed by Conrad to be the same as Lea's medellinus. Fischer and Crosse in 

 Mission Scientifique (see following reference) are doubtful about this, as Say's 

 species was never figured, and his description does not just agree with Lea's species. 

 As the type is not known to be in existence I think under the circumstances, since 

 we can not be sure of what Say described, it is best to use Lea's name. 



-The type which is in the collection of the U. S. National Museum is, without 

 doubt, a young medeUinuH. 



