U N I 0. 



I'la 



Species 431. (Mus. Lea.) 



Unio Higginsii. Un. testa nuKjnd, tmii.idd, percraisn, 

 valde liKfqitUati'rali, inboltt'iiiiie ovali, aiitice angiis- 

 tatd, postia' rotiinilnid, livri, politu, olivaceo-virente, 

 muUirad'mtd, marijnn' i-i-iilruli roiwexo, coatd uitiboiiaH 

 rotmidatd ; ared /jos/icii n/ni/i/d, cordatd, aiibplnuii- 

 latd ; nmboHibus valde emmeutibKS, tinnidii, iiiriirim- 

 tis ; Imudd parvd, distinctd ; manjaritd iilbil, aiit 

 pallide aurantio-rnbrd ; margine cardinali lata ; den- 

 tibits card ilia lib /IS nmgnis, crams, erectin, creiiidatis ; 

 dentibm lateralihits percrassis, s/ibrectis. 



HiGGiNs's Unio. Shell large, swollen, very thick, very 

 inequilateral, somewhat obliquely oval, narrowed in 

 front, rounded behind, smooth, polished, greenish 

 olive with many rays ; ventral margin convex, um- 

 bonal ridge rounded ; hinder area large, cordate, 

 somewliat flattened ; nmboes very prominent, swollen, 

 incurved; lunule small, distinct; nacre wliite or 

 salmon-coloured ; hinge-margin broad ; primai-y teeth 

 large, thick, erect, crenulated ; lateral teeth very 

 thick, slraightish. 



Le.\, Proc. Ac. N. S. Philad. 186U; Obs. on Unio, 

 vol. ix. p. 10. pi. 2-1. f. 3.58. 



Hub. .Muscatine, Iowa, N. America. 



Reminds one of Ugameidiiuis, but is less elliptical ; of 



ellipsis, but is more polished and fuller of greenish rays ; 



tif orbici/hitiis, but is more inflated, has more rays, and a 



greener epidermis. There are three indistinct raised lines 



running along the hinder area. 



Species 432. (Mus. Lea.) 



Unio decusibens. Uh. testd iixei/ni lateral i, tenni, eloii- 

 gato-oblongd, arciiatd, depresm, niitice angustatd, pos- 

 tice biangidatd, fiisco-subriifesceiite, obsolete siibra- 

 diatd, tiEvi ; margine ligamenluU ciirvato, elevato, 

 ■margine reiitrali lalissime retuso ; costd mnbonall 

 hiimili, obtiisi angnlatd ; ared posticd nngustd ; um- 

 liDiiiliiis proiiiinidis ; margaritd subpnrpnred ; deiiti- 

 biis cardi/udibns pai'vis subtransversis ; deidibi/s late- 

 ridibiis arciialis. 



The lying-down Unto. Shell inequilateral, thin, elon- 

 gated-oblong, arched, depressed, narrowed in front, 

 biangulated behind, of a somewhat red dark brown, | 



with uidistuict rays, smooth ; ligiunent mnrgui curved 

 and raised, ventral margin very broadly indented ; 

 urabonal ridge low, bluntly angulated ; hinder area 

 narrow, umboes slightly raised, nacre purplish, pri- 

 mary teeth small and somewhat transverse, latenl 

 teeth arched. 



Lea, Proc. Ac. N. S. Philad. ISGl, p. 40 ; Ohs. on Uuio. 

 vol. viii. p. 91. pi. 12. f. 236. 



Hab. Alabama, N. America. 



Reminds one, says Lea, of percoarctatns, but ditt'ers in 



shape and dentition, the primary teeth in the latter being 



nearly perpendicular to the basal margin. The lateral 



teeth are stated to be much elongated. 



Species 433. (Mus. Lea.) 



Unio Alabajiensis. Uh. testa oblongd, ventricosd, cras- 

 siiisc/ild, SHbiufeqidlatcrali, postici; obtuse biangidatd, 

 olivaceo-lidi'sceide coiicalore, inlidd, la'tigatd, margine 

 reiitrali aidice acclivi ; iiatibin promiiiidis, ad apices 

 riii/oso-imdiilatis ; costd iimbuiiali iiijiatd, rultiiidaid ,• 

 margaritd albidd, siiperm pallide aiiraiitio-riibrd; deii- 

 libiis eardinalibiis parvis, snberectis ; deiilibiis latera- 

 libiis iiidlis. 



The Alabama Unio. Shell oblong, veiitrieose, thickisii, 

 not so very iiie([uilateral, bluntly biangulated behind, 

 of a luiiform glossy yellowish olive, smooth ; ventral 

 edge rising in front; beaks a little projecting, ru- 

 gosely undulated at the tips ; umbonal ridge inflated, 

 rounded ; nacre whitish, salinon-coloured above ; 

 primary teeth small, somewhat erect; no lateral 



Lea {.Margarilaiia), I'roc. Ac. N. S. Philad. ISGl, p. 41 



Obs. ou Uuio, vol. viii. p. 108. pi. IG. f. 249. 

 Hab. Talladega Creek, Alabama. 



Allied, says Lea, who drew up his description from 

 single specimen, to SpiUmannii, \m\. dilfeis in colour, 

 less inflated, and rather more oblicpie ; its undulation 

 are, also, more concentric. 



Species 434. (Mas. Lea.) 

 Unio Wardii. Un. testd U. metanevero «(>«(////««, W 



July, 1868. 



