U N I 



Species 235. (Mus. Sowerby.) 

 Unio ventricosvs. Un. leatd infiatd, ina-qnUatornVi, 

 snhcuiieiformi, intus purpureo-aryeiited, exfiis hrvi(jatil, 

 Jiavidd, ad aream poslicam fasciis virid/dns jmitcis rn- 

 diatd; latere aiitico irevi, angusio, margine dormli 

 decllvi, margine ventrali accUvi ; latere postico lata, 

 angulato, area podanguhri parvd, margine dorsali 

 elevalo, termino acnminato, margine ventrali siirmim 

 valide acclivi, imbonibus magriis, ventricosis, margine 

 cardinali dentibus postids uno et diiobus laminatis, an- 

 ticis diiobus et uno brevibns, irregidariter crenatis. 



The ventricose Unio. Shell iiitiated, inequilateral, 

 rather wedge-shaped, silvery-purple within, smooth, 

 yellowish without, rayed with few green bauds on 

 the posterior area; anterior side short, narrow, with 

 the dorsal margin sloping, the ventral margin sloping 

 upwai-ds ; posterior side broad, angular, postangular 

 area small, dorsal mai-gin elevated, with the end acu- 

 minated, ventral margin sloiiing strongly upwards, 

 umboes large, ventrieose, hinge margin with one and 

 two posterior laminated teeth, and two and one an- 

 terior irregularly crenated. 



Barnes, Silliraan's journal, vol. vi. t. 14. f. U. 



Rub. North America. 



The cnneate form, and brond, strong upward sloping of 



the posterior ventral margin form the distinguishing cha- 



ractcvistics of this species. 



Species 236. (Mus. Hanley.) 



L'nio eaNCEOLATUS. Un. testa angustu, elongatd, coin- 

 prrs-sd, intus siibrosed, extus favidescenti, laevigata, 

 latere antico brevimcido, latere postico elongate, ter- 

 inine acinninato, snbtruncato, dentibus laterulibiis uno 

 I't dnobus posticis elongatis laniinatis, curdinalibiis in 

 iitrdqiie valvd uno prominente. 



The lanceolate Unio. Shell narrow, elongated, eom- 

 ])ressed, rose within, yellowish, smooth without, an- 

 terior side rather short, posterior side elongated, 

 with acnminated end sliglitly trnncated, lateral teeth 

 one and two posterior elongated, laminated, car- 

 dinal teeth in eacii valve one, prominent. 



Lea, Trans. \mvv. Phil. Soc. 



llab. South Carolina. 



Distinguished by its peculiar l.nnccolate oouipres«ed 



Species 237. (Mus. llaul.'v.) 

 Unio DELniiNULUS. Uu. Irstd Icnui, cuuiprcssd, si/m- 

 plignotd, ovali, margine dorsali postico perelevnto, in 

 alam proilucto, aid postice oblique subincurvn, antire 

 arcuatini abbreciato, margine dorsali antico drdici. 

 The little dolphin Unio. Shell thin, compressed, 

 symphyiiote, oval, posterior dorsal margin much ele- 

 vated, produced into a wing; wing posteriorly ob- 

 liquely rather curved inwards, anteriorly shoiuui-d 

 and curved inwards, anterior dorsal margin slojii'd. 

 MoRELET, Test. Noviss. vol. i. p. 31. 

 Hab. Yucatan. 



The curved shape of the alalr apprndage of the poste- 

 rior dorsal edge separates lliis biautiful little sliell from 

 otliers of the symphyuote form. 



Species 238. (Mas. Sowerby.) 



Unio delpiiinus. Uh. testa oblongd, coinpres.w, sgm- 

 j)lii/notn, intus alba, extus fused, beoigald, latere an- 

 tico brevi, margine dorsali rectiusculo, latere postico 

 oblique angulato, elongato, tennino otilique truucntn. 

 margine dorsali in ahiui pereh'vutiiui periionlicuhiriter 

 rugatam postice incurraui prmluclo, hiurgnu- rrutruh 

 rectiusculo, margine cardinali coiji/zressd. subrugiitu, 

 deule latera/i jmxtico hnniiiatn, elaugato. 



The dolphin Unio. Shell oblong, compressed, sym- 

 phyuote, white within, brown, smooth without, an- 

 terior side short, with dorsal margin rather straight, 

 posterior side obliquely angular, elongated, obliipiely 

 truncateil at the end, diusal niai-giu produced into a 

 nuich elevated, perpcndiiiihirly wrinkled, posteriorly 



margin compressed, rntlii'r rugn'-e, 



tooth laminar, elongated. 

 GlliiNER, Wiegmann, Arehiv, Is+l, t. 1 

 Hab. Malacca. 



No other species of nlate I'nio has so I 

 and trigonal wing, nor so .straight a vent 





\\vs\xA. ISCG. 



