U N I 



Plate LXXIV. 



Species 380. (JIus. Hanloy.) 



10 ELEGANS. Un. testd soUdd, ventricosn, snbtriaiigu- 

 kri, SHbiiifequilateraU, laviyatd, squalid^ virescfide, 

 lineis satwatioribus brevibtis acuiangnUiribm imdique 

 radiatim reticnlatd, contd mnbonaVi coiispicuci, et ualcs 

 versus aculas eminentes, valde indinatds aiigulatd ; 

 lunuld profundn, satis mnyud ; area posticd extremd 

 planulatd ; margaritd albidd ; deiitibiis cnrdlnidibus 

 valid is, pgraniidalihiis. 



E ELEGANT Unio. Shell very strong, ventricose, sub- 

 triangular, less inequilateral than usual, not sculp- 

 tured, of a (lull greenish hue, painted with approxi- 

 mate radiating rows of short dark acutangular lines, 

 which form a kind of net-work over the entire sur- 

 face; ventral margin much arcuated, especially be- 

 hind ; umbonal ridge well marked, angular near the 

 beaks, which are prominent, acute, and much in- 

 clined ; lunula deep, rather large; umbonal slope 

 flattened ; nacre white ; cardinal teeth strong, large, 

 pyramidal. 



A, Obs. on Unio, vol. i. pi. 19. f 13. 



Uiiio trnncatits. Say (lis of lUif.), Am. Con. ])1. G7. 



/;. lUvers Wabash, Scioto, Ohio, etc., N. America. 



fowards the lower corner of the umbonal slope, which, 



well as the vicinity of the lunule, is greenish-yellow, 

 zigzag markings are changed into broken radiating 



?s ; the angular ones upon the disks have their points 



eeted towards the beaks. 



dent ill front than behind, embossed on the umbonal 

 region with large radiating folds, which do not 

 usually reach to the broad concave and compara- 

 tively smooth umbonal slope ; dorsal margin falling 

 in front, rising and angulated behind ; ventral mar- 

 gin rising at both extremities ; umbocs somewhat 

 broad, rather prominrnt , nacre bluish-white ; cardi- 

 nal teeth lauiellai-. 



Maton, Tr. Linn. Soe. vol. .\. ]). 3i7. pi. 2J-. f 4-7. 

 Unio rnfiiilraiiaceits, Philippi. 



Hub. Eio de la Plata, S. America. 



The anterior side is much narrowed by the sudden fall 



of the dorsal line, which rises behind the umboes so as to 



give a wing-like appearance to that portion of the shell. 



Species 381. (Mus. Hanlcy.) 

 Unio variabilis. Uh. iestd ieiiui, hand niagnd, obo- 

 vato-suhrhomboided, antic'e arigusfd, postice magis 

 miintsve veidricosd, fiavo-olivacea, concolore, liris iii- 

 crementi (prasertim auiicej cojifertim corrugatd, su- 

 peri/e plicis magids radial a ; ared posticd dorsali 

 laid, kevigald ; margiue dorsali atitice dmiisso, pos- 

 tice acclivi, angulato ; margine ventrali utrinque ac- 

 elivi ; nmboiiibus latiuscuUs, satis eminentibus ; mar- 

 garitd albido-carulescente ; deiitibas cardinalibus la- 

 in i//al is. 

 The variable Unio. Shell thin, not large, obovate- 

 subrhom!)oi(l, narrow in front, more or less swollen 

 behind, of an uniform olivaceous yellow, with close- 

 set raised wrinkles of increase, which are more evi- 



Species 383. (Mus. Hanley.) 

 Unio ellipticus. Uh. testd pared, compressd, siiborali, 

 olivaced, hand radiatd, antice prope nates nidi corru- 

 gatd, postice lavi ; margine dorsali postico luiud de- 

 cUri ; 1,1(1 njiiie ventrali eoi/rexo, vix minimi retuso ; 

 liuinld niilhi ; natibtts rugis elevatis (antice sabgra- 

 nosixj cunceiitrice oriiaiis ■ margaritd albido-Cfcrii- 

 lesceide ; dentibus cardinolUms laciiiiatis, Jwiid Iraiis- 

 versis. 

 The elliptic Unio. Shell small, compressed, svdwvai, 

 olive-coloured, not rayed, coarsely n-rinkled in front 

 near the beaks, smooth behind ; hinder dorsal margin 

 not sloping, ventral margin convex, scarcely in- 

 dented, no distinct lunule ; beaks adorned witli raisril 

 corrugations, which are somewhat granular in front ; 

 nacre bluish-white; cardinal teeth jagged, not trans- 

 verse. 

 Spix, Test. Bras. pi. 20. f. 1, 2. 

 Unio hiultistriatiis. Lea. 

 Unio psumrnactinns, Bronn. 

 Hab. Bahia, Brazil. 



A few raised divergent lines are usually visible at the 

 commencement of the umbonal slope, which is not de- 

 fined by a marked ridge. The valves are rather thin, and 

 their nacre is disfigured by olivaceous stains in the um- 

 bonal cavity. 



Species 383. (Mus. Hanley.) 

 Unio Ouegonensis. Un. testd validd, sitbiiuequilaterali, 

 elongato-subovali, postice obtusissime subbiangidatd. 



March, 1868. 



