NO. 1205. SYNOPSIS OF THE NAJ AD ES— SIMPSON. 573 



II, 1857, p. 492.— *SoWERBY, Conch. Icon., XVI, 1868, pi. Lxvi, tig. 336.— 



* B. H. Wright, Check List, 1888.-*PiETEL, Conch. Sam., Ill, 1890, p. 149.— 



* Fischer and Crosse, Miss. Sci., Pt. 7, II, 1894, p. 6L5. 

 '^Margarita ( Vnio) cuprinus Lea, Syn., 1836, p. 39; 1838, p. 25. 

 *Mar(iaron (Unio) cnprinus Lea, Syn., 1852, p. 38; 1870, p. 61. 



^^ Unio aereiis Reeve, Couch. Icon., XVI, 1856, pi. xxx, fig. 160.^ — * P^etel, Couch. 

 Sam., Ill, 1890, p. 144. 



Mexico. 



(Group of Lampsilis gracilis.) 



Shell large, tbiii, elliptical or slightly obovate, with a high posterior 

 and an anterior wing, not greatly inflated; beaks low; e[)idermis rather 

 smooth, often feebly rayed, dull colored, but usually glossy; hinge line 

 slightly and rather regularly curved ; teeth compressed, pseadocardinals 

 but feebly and often imperfectly developed; nacre purplish tinted, 

 rather dull. Shell of the male and female nearly alike, the latter 

 scarcely swollen at post basal region. Animal with the mantle greatly 

 thickened at posterior end, and double and thickened at j)0st base, 

 where it is often crenulate or toothed on its inner border, and has the 

 outer developed into a flap; inner gill united to the abdominal sac 

 throughout; marsupium enormous, composed of a great number of 

 delicate semiradiating ovisacs, projecting far below the inner gills in a 

 semicircle. 



fLAMPSILIS GRACILIS Barnes. 



"Unio gracilis Barnes, Am. Jl. Sci., VI, 1823, p. 274. — ' Hildreth, Am. Jl. Sci., 

 XIV, 1828, p. 288.— *Deshayes, An. sans Vert, 2d ed., VI, 1835, p. 559; 3d 

 ed., II, 1839, p. 676; Tr. Element. Couch, 1839, p. 18, pi. xxx, figs. 2, 3.— 

 *Hanley, Test. Moll., 1842., p. 174. — ''C. B. Adams, Thompson's Hist. Ver- 

 mont, 1842, p. 166; '' F. W. and L. Shells of Vermont, 1842, p. 16.—" Hanley, 

 Biv. Shells, 1843, p. 174, pi. xx, iig. 37. — * Catlow and Reeve, Conch. Nom., 

 1845, p. .59.—^ Deshayes, Tr. Elem., II, 1853, p. 217, pi. xxx, figs. 2, 3.—^ H. 

 and A. Adams, Gen. Rec. Moll., II, 1857, p. 498. — ""Sowerby, Conch. Icon., 

 XVI, 1868, pi. XXXIX, fig. 215.—* Calkins, Pr. Ottawa Ac. Sci., 1874, p. 42.— 

 *Latchforu, Tr. Ottawa F. Nat. Club., 1882, p. 52.— *B. H. Wright, 

 Check List, 1888. 



*Mya gracilis Eaton, Zool. Text Book, 1826, p. 222. 



* Symphyyiota gracilis Lea, Tr. Am. Pbil. Soc, III, 1830, p. 452. — Short and 



EatOxX, Transylvania Jl., 1831, p. 80 — * Lea, Obs., I, 1834, p. 66. 

 ^Margarita {Unio) gracilis Lea, Syn., 1836, p. 11; 1838, p. 13. 



* Meiaptera gracilis Stimpson, Shells of N. Eng., 1851, p. 14. 

 ^ Mar gar on (Unio) gracilis Lea, Syn. 1852, p. 19; 1870, p. 28. 



* 1 Anodon gracilis Sowerby, Genera, No. XVII, 1823, fig. 



* Lampsilis gracilis Baker, Moll. Chicago, Pt. 1, 1898, p. 99, pi. xix, fig. 1. 



* Unio fragilis Swainson, Zool. 111., 1st ser.. Ill, pi. CLXXi, 1823.-' — * Deshayes, 



Encyc. Meth., II, 1830, p. 587.— * Say, Am. Conch., VI, 1834.—* Conrad, New 

 F. W. Shells, 1834, p. 69; *Monog., VI, 1836, p. 55, pi. xxx.— *Chenu, Bib. 



^The description of the plate is dated 1856, and in the contents it is credited to 

 Reeve, although the previous plates bear date of 1865, and those following 1866. 



^Swainson's Unio fragilis Avas jjublisbed about the same time as Barnes's gracilis, 

 and as it is impossible for me to say which has priority, I agree with Lea that it is 

 better to adopt Barnes's well-known name. 



