U N I 



Species .iol. (Mus. Brit.) 



Unio Burtoni. Uh. tesia parvd, snbrotmuh-ovali, pa!- 

 lide draminea, aritice lavigatd, ad margineui dioarica- 

 ilm sulcata, medio et posfice acute, aiirjuhiiini, el 

 crehre sulcata, iutus alLidd ; latere poatico ohlongo, 

 term'mo acunthiato, marginc dorml'i snhelevalo ; latere 

 auticd breomtiiio, rotmido, umboiiihiis parvis, deiitibiis 

 cardiiialibns augustis. 



Bukton's Unio. Sliell small, rather roeaully oval, pale 

 straw-coloured, smooth in i'rout, divevgentiy i^vooved 

 at the edge, sharply, angularly, and closely sulcated 

 in the middle and at the back, whitish within ; poste- 

 rior side oblong, acuminated at the end, with dorsal 

 margin slightly raised; anterior side very short, 

 round, umboes small, cardinal teeth narrow. 



Woodward, Pro. Zool. Soc. 1859, p. 348. 



ffab. Tanganika, Central Africa. 



With the e,\ception of a portion of the anterior side, 



the surface of this shell is covered with close zigzag 



sulci. 



Species 253. (Mus. Hanley.) 

 Unio SUBPLANUM. Uu. tedii nubquaJrald, erasm, Intd, 

 tumklii, valde hifequilalerali, intm alba ; latere poa- 

 tico magrio, biai/gulato, inter angulos late planato, 

 post augulum poslicum subtrigona, margiiie dorsali 

 redo, elevato, margine termbiaU supra deelivi, infra 

 truMcatd, margine ventrali ante augulum subconlraclu, 

 tuiii injlato ; latere at/tico brevissimo, Heunrolmido, 

 ejiiilermide cransd, nigra. 

 The nearly flat Unio. Shell subqnadrate, thick, 

 wide, tumid, very inequilateral, white within ; pos- 

 terior side large, with two angles, between the angles 

 widely flattened, behind the posterior angle subtri- 

 gonal, dorsal margin straight, elevated, terminal 

 margin sloping above, truncated beneath, ventral 

 mai^iii rather contracted in front of the angle, then 

 swelled ; anterior side very short, half-round, epi- 

 dermis thick, black. 

 Conuad, Monograph of Unio; Virginia. 



Species 353. (Mus. Ifanlcy.) 



Unio Greknii. Un. laid oblongd, eraam, subobliijud, 

 lievigiitn, iutiis albidd ; latere postico oblongo, oblique 

 hiaiujiihito, inter angulos obliqtCe truncalo, snbplanato, 

 margine dorsali rectiuscn.lo, mari/ine rm/rnli injlato : 

 latere anlico brevissinio, deelici. ejiiilri-mid,- o/ii-aceo. 



Gi;ekn".s Uxio. Shell oblong, thick, siibi)l)liiiue, smooth, 

 uhite within ; posterior side oblong, obU.pieiy iloubh- 

 aiiglcd, obliquely truncated, nearly tlat lictueiMi the 

 angles, dorsal margin rather straight, ventral margin 

 inflated; anterior side very short, sloping, epidermic 

 olive. 



CoNMiAD, New Freshwater Shells. 



Jlnb. Viririnia. 



Species 254. (Mus. Cuming iu Brit.) 



Unio HaINE.sIAXUS. !'n. lesld ruhmdii, leniii, injlalii, 

 heeigulii, valde intrquilaU-ntli, epidcrniide riridi, snfj- 

 aurril inJntd, untiri' conrenlriri- plirnld ; later,- pos- 

 tico tninid,,, injhitu, v.nujna, nhiln, nksmri' Irianijnlatu, 

 margiiir ,lorx,iii I'lrnitu, area sidiuiin-(jinuli dicurica- 

 tin: jilirni,: . i,nir,:iiii' trnniniili inter angulos truncato, 

 miinjiiii- rciilr.ili rnnre.ri) ; lalere anlico breci, ro- 

 tunda, margine cenlrali snrsuui iicclici, uinbo)nbus ro- 

 tundis. 



Haines's Unio. Shell mund, thin, inflated, smooth, 

 very incindateral, invested with a ureen, slighlly 

 golden-finted epidermis, conpenti'ieally plicated in 

 front; posterior side tumid, iidhited, large, winged, 

 with three obscure angles, dorsal margin raised, sub- 

 nuirginal area divergently plaited, terminal margin 

 truncated between the angles, ventral margin convex ; 

 anterior side short, ro\iud, ventral margin sloping 

 upwards, innboes ronmled. 



Lea, l/iiio, vol. vi. p.S*. pi. 21. f. 4. 



JInb. Uitlle Arkansas. 



Of all the large ahite species, this has the greatest ro- 



tuuditv and fuhiess of form. 



Species 255. (Mus. Cunung in Brit.) 

 Unio Postellii. Un. lesld oblumjd, erassd, snbr/ioui- 



Noveudjer, ISfjt 



