U N I . 



Pi.ATK lAxvin. 



SpcncN -tor,. (Mu^. Haiil.N.) 



iNin DlandiaXUS. U,i. leslii nlu»ihdn.,,,„uh-aUi, xiih- 

 inaqiiilaleraU, teniricosic, in medio rm/ia//,,/ i-viicnni, 

 liavo-oUvaced concolore, costd iimboiKili 11111^^11,1(1 um- 

 iiilii, coiicentrice rude suhplicald, auticP H in areain 

 jioxficai,! dorsalm laiam el concavam vernicis com- 

 pn'ssi.i Innje ornuld, mimjiue vmtrali iiicurvntn, mar- 

 ffine dorsali podico vix decUn, umbonibm emineiilibiis, 

 margarita albd; denlibus cardinalibiis maf/ids, laci- 

 viatis, pp-amidalibus. 



IiLand's Unio. Shell rotundately square, not very in- 

 equilateral, ventricose, with a ray-like hollow in the 

 middle, of an uniform yellowish-olive, with a pecu- 

 liarly broad umboual ridge, coarsely subplicated cou- 

 Cfutrically, ])rofusely adorned in front and upon the 

 liroad and concave uuibonal slope with pinched, 

 wait-bke knobs, ventral edge incurved, hinder dor- 

 sal edge scarcely sloping, umboes prominent, nacre 

 white; cardinal teeth big, jagged, pyramidal. 



Lea, Journ. Ac. M. S., Philad. ser. 2. vol. iv. (and Obs. on 

 Unio, vol. vi. p. 65), pi. 11. f 47. 



Hub. Coosa river, Alabama, and Othcalooga Creek, 

 Georgia, N. America. 

 The posterior tubercles are an'anged in more or less 



ri'gular curved diverging rows. The stages of growth 



arc close and subpliciform. 



Species 406. (Mus. Hanley.) 



^Nlo TuoosTENSIS. Un. testd parvd, validd, vel subob- 

 liqiie orald, vel obhngd, valde iniBqidlakndi, anticit 

 subbiangulald, siibvenlricosd, lavi, olivaced, liueis con- 

 feiii'i drigiaque aiiguslis saturalioribus undique (minun 

 iiiilriii iiiilice, el nomtunquam obscuHsj radinld, mar- 

 (jiiii- i-eutruli subi-eluso, et antice acclivi, and posited 

 dorsiili coiicavd, umbonibus satis emiHentibus, litimld 

 profundi excavatd, margarild albd, denlibm cardina- 

 libiis mngnis, InciniaUs, Iriyonis. 



'uoost's Unio. Shell small, strong, either somewhat ob- 

 lii|nely ovate, or oblong, very inequilateral, subbiangu- 

 latcd in front, somewhat ventricose, smooth, olive, 

 cveiywlirre (less in front, and at times indistinctly) 

 rayed with darker narrow streaks and crowded lines ; 

 ventral margin somewhat indented, rising in front, 

 uud)onal slope concave, umboes moderately prominent. 



i|ily ( xcavated, nacre white, primary teeth 



Lka, Trans. Amer. Phil. Soc. ser. 2. vol. v. (and Obs. on 

 Unio, vol. i.), p. 71. pi- 10. f. 30. 

 Uniu Irabu lis. Conrad. 

 Hab. Cinuberlaiidri\er. X. America. 



It was impossible for Conrad to detect in the elongated 

 male exanipli' delineated by Lea, his obliipiely ovate Ira- 

 balis. These sexual distinctions (which are not salient in 

 other shells) are a source of continual difhculty in the 

 American Naiades. The species is quite distinct from the 

 one erroneously so termed in Plate XXXVIll. 



Species 407. (Mus. Hanley.) 



Unio striatus. Un. lesld parvd, solidiusculd, nilidd, 

 ovuli, postice rolundnto-subbiangulatd, vix subeenlri- 

 cosd,Jlavo-si(boUmced concolore, concentrice subslriald, 

 margine venlrali convexo. cosld nmbonali inconspicud, 

 Innnld nnlld, nalibiis vix eMiuenHbus, margarild 

 ciipred, denlibiis cardinalibiis lacinialis, subpi/ramida- 

 libiis. 



The striated Unio. Shell small, rather strong, glossy, 

 oval, rotundately subbiangulated behind, barely sub- 

 ventrieose, of an uniform somewhat olivaceous yel- 

 low, concentrically substriated ; ventral edge convex, 

 umbonal ridge inconspicuous, no lumde, beaks 

 scarcely projecting, nacre copper-coloured ; primary 

 teeth jagged and somewhat pyramidal. 



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

 on Unio, vol. iii. p. 41), pi. 12. f. 16. 



Hab. Chattahoochie river. Columbus, Georgia, N. Ame- 



Species 408. (Mus. Hanley.) 

 Unio nicer. Un. lesld ovalo-acuminald, solidissimd, 

 satis ventricosd, subolimced, obscure radiuld, lamgatd, 

 postice cuneifonni, margine dorsali antico convexo, 

 satisqiw declivi ; margine venlrali convexo, vix minime 

 reluso, antice arciialiin acclioi, cosld nmbonali anyit- 

 hitd, area poslicd planulatd, umhonihus talis, limuld 

 vuignd. excavatd, margarild albido-livescenle, margine 

 curdinnli lato, dentibus cardinalibiis pgramidalibiis, 

 denlihns luleralibiis criissis. 

 The black Unio. Shell peaked ovate, very solid, mo- 



