UNIO.— Plate LXXXVl. 



Species 460. (Mus. Taylor.) 

 Unio striatissimus. Uh. testa crassiutcnld, dqiressd, 

 siihrhomhoidea, subinaiquilateraU, postice late bianiju- 

 latd, stramined seu flavescente, coticolore, concentrke 

 rude rugosd, margine ventrali aniice arctcatim acclwi, 

 coda umbonali suhangulatd vix elevald ; lumdd im- 

 pressd, lanceolatd; natibtcs acutis, ad apices tan turn 

 plicis perpauck oliliquis imdulatis ; margaritd al!)d, 

 margine cardinali lata dentibns cardinalihus siiblri- 

 gonis laciniatis, at lamellis obliquis rectis percrassis, 

 iiistructo. 

 The much-striated Unio. Shell thickish, depressed, 

 subrliomboid, subiiieqiiilateral, broadly biangular be- 

 hind, yellowish or straw-coloured, not variegated, 

 concentrically coarsely wrinkled ; ventral edge arch- 

 ing upwards in front; umbonal ridge subangular, 

 scarcely raised ; lunule impressed and lanceolate, 

 beaks acute and, at their tips only, waved with a very 

 few slanting folds, nacre white ; hinge-margin broad, 

 provided with jagged subtriangular primary teeth, 

 and very thick straight oblique lamella;. 

 Anthony, Amer. Jouni. Conch. 1S6.5 (vol. i.), p. 155. 



pl.l2. f. 1. 

 Hab. Tennessee. 



The irregular corrugation becomes coarse witb age, but 

 the umbonal surface is merely striolate. The lateral teeth 

 do not follow the dorsal line, but run downwards with pe- 

 culiar obliquity. 



Species 4R1. (Mus. Sowerby.) 

 Unio Astieranus. Uh. testa hand rnngnd, ovato-ob- 

 loiKjd, solidd, ventricosd, subinaqiiilaleraU, antice por- 

 rectd et rotundatd, postice subbiaiigidatd, bruiined coti- 

 colore, coucentrice riigosiusculd, ad umboiies eminentes 

 porcis late uttdatis conspicue instructd ; margine ven- 

 trali antice arcuato, uatibus acutis, involutis, lumdd 

 impressd, margaritd alba, margine cardinali lato ; 

 dentibus cardinalibus subtrigonis, laciniatis ; dentibus 

 lateralibus validis. 

 Astier's Unio. Shell not large, ovate-oblong, solid, 

 ventricose, only moderately inequilateral, rounded 

 and peculiarly projecting in front, subbiangulated 

 behind, of a uniform brown, concentrically sul)rugose, 

 conspicuously marked on the prominent umboes with 

 broadly waved ridges ; ventral edge arched in front, 

 beaks acute and involute, lunule impressed, nacre 

 •white, hinge-margin broad, primary teetli j:igged and 

 subtriangular, lateral teeth strong. 

 Duply, Moll, de France, p. 636. pi. 33. f. 9. 



U. cunealm, Rossmiissler fas of .Jacq.). 

 TIab. Aries, S. France. 



Allied to Utoralis, but easily distinguished by the nar- 

 row square-cut ridges, which abruptly terminate at an 

 acute angle before the umbonal slope. 



Species 463. (Mus. Ilanley.) 



Unio Stonensis. Uh. testa solidd, depressd vet con- 

 vexd, oblonyd, valde incsquilaterali, inferne subretusd, 

 fitsco-Jiavescente concolore, sublavigatd, costd umbo- 

 nali htmili, limuld angustd, natibus prominulis ad 

 apices minute midulatis, margaritd pallide rnbro- 

 aurantid vel purpurascente ; dentibus cardinalibus 

 jjrofiindi striatis, pgramidalibus ; dentibus lateraUbus 

 validis, elongatis. 



Stones's Unio. Shell solid, compressed or convex, ob- 

 long, very inequilateral, somewhat retuse below, of a 

 uniform yellowish-brown, smoothish ; umbonal ridge 

 not raiseil, lunule narrow ; beaks slightly prominent, 

 minutely undulated at the tips ; nacre salmon-coloured 

 or purplish ; primary teeth deeply striated, pyrami- 

 dal ; lateral teeth strong, elongated. 



Lea, Trans. Amer. Phil. Soc. ser. 2. vol. viii. (Obs. on 

 Unio, vol. iii. p. 33), pi. 8. f. 5. 



Hab. Stones's Eiver, Tennessee, America. 



Species 463. (Mus. Hanley.) 



Unio Hochstetteri. Un. iestd crassiusculd, depressd, 

 valde inaquilaterali, aniice perbrevi et angustd, pos- 

 tice late biangulatd, subatatd, olivaceo-n igrescente con- 

 colore, in tnediand parte obsolete subverrucosd, alibi 

 sublavigatd ; margine ligamentali curvato et acclivi, 

 ared posticd concavd, lunuld nulla; margaritd albido- 

 carulescente, vmcidis olivaceis variegatd; dentibus 

 cardinalibus subtransversis ; dentibus lateraUbus elon- 

 gatis, ad apices valde elevatis et oblique truncatis. 



Hochstetter's Unio. Shell thickish, depressed, very 

 inequilateral, narrow and very short in front, broadly 

 biangular and somewhat winged behind, of a uniform 

 blackish olive, very indistinctly subverrucose in the 

 middle, elsewhere unsculptured ; ligamental edge 

 curved and rising, hinder area concave, no lunule ; 

 nacre bluish-white, variegated with olive ; primary 

 teeth somewhat transverse ; lateral teeth elongated, 

 much raised and obliquely truncated at their extre- 

 mities. 



DuNKEit, Malak. Blatter, vol. viii. (ISGll, p. 153. 



Hub. Lake Taupo, N. Zealand (teste Dunker). 



