U N I 0. 



Plate LXXXVIII. 



Species 470. (Copied from Moricand.) 



Unio costulatus. TJii. testa ohlomjd, venlrkom, valde 

 inreqidlateraH, postice subattenuatd et rolumlato-hian- 

 gulatd, tetiebroso-olivaced concolore, radialim costii- 

 latd ; costulk posticis remotioribm^forliorUtus ; mar- 

 ffine dorsali antico humili ; margiiie veiUrali antice 

 acctivi, postice inciirvato ; natibus emiiioitibus et valde 

 obligitis ; margaritd albo-caerulesceiite ; dcnte cardiiiali 

 crasso aciitu in utrdqne valvuld, lamellis lateraUhiis 

 nullia. 



The thin-ribbed Unio. Shell oblong, ventricose, very 

 inequilateral, somewhat tapering and rotundately bi- 

 angulated behind, of a uniform dark olive, with nar- 

 row radiating ribs, which are stronger but further 

 apart posteriorly ; front dorsal edge low ; ventral 

 edge rising in front, much indented behind ; beaks 

 projecting, much slanting ; nacre bluish-white, a 

 single thick and acute primary tooth in each valve, 

 no lateral lamina;. 



MoiucANU, Rev. et Mag. Z. 18.58. pi. 15. f. 1. 



ILib. Brazil. 



llic epidermis is somewhat loose. 



Species 471. (Copied from Lea.) 



I'lNMo RowELLii. U)i. testa parm, cramuscidd, vix si/b- 

 vei/tricosd, siibiiueqiiilate}-ali, ellipticd, couceutrice sul- 

 cata, riifa-fuscd, obscure radiatd, casta umboiiali ro- 

 Inndatd vixqiie elevatd, natibm prominnlis ad apices 

 miii/ite undulatis, margaritd alba ; dentibus cardiiiali- 

 biis coii/pressis, elevatis, creiiitlalis ; dentibus laterali- 

 lius subrectis, satis elongaiis. 



Howell's Unio. Shell small, thickish, scarcely even sub- 

 ventricose, subinequilateral, elliptic, concentrically 

 grooved, reddish-brown ; unibonal ridge rounded and 

 scarcely raised, beaks slightly projecting and minute- 

 ly undulated at the tip, nacre white ; primary teeth 

 compressed, elevated, crenulated ; lateral teeth 

 straightish, tolerably long. 



Lea, OI)s. on Unio, vol. vii. (Journ. .Vc. Nat. Sc. Philad. 

 ser. 3. vol. iv.), p. 74. pi. 40. f. 136. 



Kab. Chargres river. New Granada. 



The reddish-brown of the epidermis inclines to olive, 



and the ligament is light brown. 



Species 472. (Copied from Lea.) 



Unio AVilsonii. Un. testa tenui, depressiusculii, obhmgn- 

 ellipticu, iiiferne subretusd, couceutrice coufertim lenui- 

 siitcatd, nitidd, olivaceo-viridi, obscure radiatd ; costd 

 uhilioiiaU rotmidatd, vix elevatd; hinuld nulla, natibus 

 proiidmdis haudque insculptis, margarild albo-carn- 

 lescente ; dentibus cardiimlibus parvis, obliquis, lamel- 

 latis ; dentibus lateralibus elongntis, subrectis. 



Wilson's Unio. Shell thin, rather depressed, elliptic- 

 oblong, somewhat refuse below, with delicate and 

 crowded concentric grooves, shining, olive-green, ol)- 

 scurely rayed ; nmbonal ridge rounded and scarcely 

 raised, no lunulc, beaks a little prominent ami not 

 sculptured, nacre bluish-white ; primary teeth small, 

 oblique, lamellar; lateral teeth long, straightish. 



Lea, Obs. on Unio, vol. vii. (Journ. Ac. Nat. Sc. Philad. 

 ser. 3. vol. iv.), p. 74. pi. 40. f. 137. 



Hab. Isaac's Plain, New S. Wales. 



The primary teeth are double in the right valve, single 



in the left. 



Species 473. (Copied from Lea.) 



Unio Plantii. Ua. testd crassiusculd, valde compremi, 

 ellipticd, incequilateraH, lavi, nitidd, fusco-casta/ied, 

 margine ventrali arcuato, costd unibonali huinili el 

 rotundatd, natibus prominnlis, innrgaritd pallide au- 

 rantio-rubrd ; dentibus cardinalihus liaud magnis, ob- 

 tuse conicis, crenulatis ; dentibus lateralihus prcehngis, 

 curvatis, corrngatis. 



Plant's Unio. Shell rather thick, much compressed, 

 elliptic, inecpiilateral, smooth, shining, of a uniform 

 dark chestnut ; ventral edge arcuated, umbonal ridge 

 low and rounded, beaks a little projecting, nacre 

 salmon-coloured; cardinal teeth rather small, ob- 

 tusely conical, crenulated ; lateral (eelh very long, 

 curved, corrugated. 



Lea, Obs. on Unio, vol. vii. (Journ. Ac. Nat. Sc. Philad. 

 ser. 2. vol. iv.), p. 10. pi. 31. f. 7(i. 



Hab. Flint river, near Macon, Georgia, U. S. America. 



Described l)y Lea from a single specimen, the beaks of 

 which were much erodeil. 



Species 474. (Copied from Lea.) 

 Unio Conxasaugiiensis. XJn. tedd tenuissimu, ubtu 



September, ISOS. 



