IgI2. | H. B. Preston: The Asiatic Navades. 305 
p. 22, pl. xlvi, fig. 7,—Margaron (Unio) generosus, Lea, Syn., 
1870, p. 29,—= ?Unio lamellatus, Sowerby. Conch. Icon., XVI, 
1868, pl. xciv, fig. 511. 
Myadong, Upper Burma (J. Anderson), Reg. No. 2931; Man- 
dalay (N. Annandale), Reg. Nos. +7252"; Bhamo (J. Coggin Brown), 
Reg. No. L736, 
76). Var. jenkinsianus (Benson) ,—Lamellidens jenkinstanus , 
(Benson) in Simpson’s Syn. Naiades, Proc. U S. Nat. Mus., XXII, 
p. 857,—Unio jenkinsianus, Benson, Ann. Mag. Nat. Hist., Ser. 3, 
X, p. 185 ; Hanley and Theobald, Conch. Ind., pl. xli, fig. 4. 
Upper Assam, Reg. No. 2446; Sylhet, Reg. No. 5937; Upper 
Bramaputra (F. Stoliczka), Reg. No. #87; Bhagalpur (Capt. 
Sherwill), Reg. No. +878, 
76k. Var. zonatus, Deshayes,—Umio zonatus, Deshayes, Enc. 
Méth. Vers., II, p. 587; Hanley and Theobald, Conch. Ind., pl. 
sliv;-fic. 2: 
Rangoon, Reg. No. 525s, 
76l. Var. sublamellatus (Nevill, MS.) var. n. 
An elongate, somewhat rostrate form, having the hinge teeth 
rather less developed. 
Hab.—Burma (W. Theobald), Reg. No. +711 [Type]. 
76m. Var. sawaddyensis (Nevill, MS.) var. n. 
Shell much more ovate and convex than the typical form, 
having the dorsal margin more arched and posteriorly ascending, 
the ventral margin and anterior side more rounded, and the pos- 
terior side produced and roundedly rostrate. 
Hab.—Sawaddy River (Asiatic Society of Bengal), Reg. No. 
2911 [Type]; Bhamo (J. Anderson), Reg. No. +791; Sawaddy, 
Tengling Stream (J. Anderson), Reg. Nos 2525 and 2528; Shuay- 
goomya, Upper Burma (J. Anderson), Reg. No. 2582; Mandalay, 
Upper Burma (N. Annandale), Reg. Nos. +729—2", 
77. Lamellidens narainporensis, sp. n. 
Shell cuneate, moderately convex, posteriorly rostrate, dark 
reddish brown, covered, towards the margins, with a finely lami- 
niferous periostracum, marked with concentric lines of growth, 
bearing two carinae on each valve running from the umbones in a 
dorsally posterior direction ; umbones small, not prominent, some- 
what coarsely corrugated; dorsal margin very gently arched ; 
ventral margin scarcely rounded in the anterior and median 
regions, slightly curved posteriorly; anterior side abruptly 
rounded ; posterior side sloping above, then angled and very 
abruptly descending ; cardinal tooth in left valve obtusely tri- 
angular, erect, absent in right valve ; lateral teeth anteriorly short, 
deeply grooved and projecting in right valve, erect and jagged in 
the left, posteriorly moderately elongate and bifurcated in both 
valves ; anterior scars rather circular, deep ; posterior scars lightly 
impressed ; interior of shell pale flesh colour shading to iridescent 
bluish white, very minutely granulate, 
