UNIO.— Plate 



fiircalis) uiii/ii/iie uniald ; margarila albklo-candes- 

 ceiUe ; denliljKs c<irdiiiaHbu.i in utrCujHe valvuld 2, 

 ereclls, triguitis, lacinudk ; laiiicUh lalerallbiis cur- 

 vad-s, elcrat'is. 

 I'ioykin's Unio. Shell more or loss tiiick, ventricose in 

 the middle, very inequilateral, subtriangularly obo- 

 vate, ill front very short narrowed and rounded, 

 behind broad depressed and winged, of a uniform 

 blackish-olive, eveiywhere adorned with numerous 

 slanting subarcuated or flexuous (and often forked) 

 folds ; nacre bluish-white ; primary teeth two in each 

 valve, erect, triangular, jagged ; lateral lamellae 

 curved and elevated. 

 Lea, Trans. Amer. Ph. Soc. ser. 2. vol. viii. (Obs. on 



Unio, vol. iii. p. 46), pi. 18. f. %i. 

 Rah. Chaltachoocliee River, Georgia, and Warrior River, 

 Alabama, U. J>. 

 The hinder dorsal area is broadly concave, and the 

 liinge-margin is only broad where it serves as a base for 

 the primary teeth. In the closely allied lieroi the folds 

 near the ligament are small, narrow, and numerous. 



Species 2. (Mus. Cumin- ) 



.\s the shell represented proves to be a dwarf form of 

 Unio fragosus, of which a fine and characteristic example 

 has been delineated in Plate VII. (Fig. 27), the reader is 

 referred to the description there appended. 



Species 3. (Mus. Cuming.) 

 Unio Schoolcraftensis. Uh. tedd cra.mn.icuM, s/ib- 

 ventrkosn, subquadrato-rotundd, vi.t inceqiitlateraU, 

 ntitici late rotundatd, posiice sMiangulald, n'ltida, 

 Jlavd, radio perviridi lata et brevi in medio sujieriii 

 pictS, iuberculia planulnlis salisque magnis in medio 

 infenie, alikqiie miuoribiis in et supra eostam nmbo- 

 nalern suhangulatani (in e.mnjilis odnllix) sparsim 

 ornatd ; umtjonibm enuneiililin\ . nuinjarild albido- 



cterulea , 



nine cardiiioli di-nlilii. 



nyoiii: 



rlica- 



libus, lamelliiiqiie lateraHbus i:u/idi.s et ri..r elungatis 

 mnuito. 

 Schoolcraft's Unio. Shell tiiickish, subventrico.se, 

 squarish-orbicular, broadly rounded in front, subbiau- 

 gular behind, of a shining bright yellow, painted 



above with a short broad central green ray, here and 

 there adorned below (in full-grown specimens) with 

 central tubercles which are flattened and rather large, 

 and on or beyond the siibangular umbonal ridge with 

 other smaller ones; umboes projecting; nacre bluish- 

 white ; hinge-margin broad, strengthened with ver- 

 tical triangular teeth, and strong, scarcely elongated, 

 lateral lamellre. 



Lea, Trans. Amer. Phil. Soc. scr. 2. vol. v. p, 87 (Obs. 

 on Unio, vol. i.), pi. 3. f. 9. 



Ilab. Fox River, Green Bav, N. America. 



Species 4. (Mus. Cuming.) 



Unio verrucosus. Un. tedd crassd, depressi/isni/ii, ui 

 medio return, oblongo-subqiiadratd, valde inrrqnihiti-- 

 rali, postice subbiangulatd, olivaced concolon-, a,ilr 

 eostam umbonalem elevatnm rerriicis coiifertissimix 

 uiidigue sculptd, et ultra earn plicis divergeiitib/is sub- 

 arcuatis oblique ornatd; margine venlrali antic'!- 

 acclivi, postice retuso ; natibus parris, o/jliquis, rixque 

 promiiiidis ; margariid albo-nrgented ; margine cnr- 

 dinali Into ; dentibus curdinalibus erectis, subtrigvnis, 

 laciuiatis ; Inmellis la/i-rulibiis longis rei-tis, der/i- 

 vibiis. 



TuE WARTY Unio. Shell thick, rather depressed, in- 

 dented in the middle, squarish-oblong, very inequi- 

 lateral, subbiangular behind, of a uniform olive- 

 green, before the raised umboual ridge everywhere 

 embossed with most crowded warts, and beyond it 

 slantingly adorned with somewhat curved divergent 

 folds ; ventral edge rising in front, indented behind ; 

 beaks small, slanting, scarcely projecting; nacre 

 silvery white; hinge-margin broad; primary teetii 

 erect, subtriangular, jagged ; lateral lamelhv long, 

 straight, oblique. 



Rafinesque, Mon. Coq. de la Riv. Ohio, Ann. Gen. Sc. 

 Phys. Brux. 1820, vol. v. pi. SI. f. l(i-12. 

 U/iio tuberculatits, Barnes. 

 Theliderma pwstulata, Swainson. 



Hab. River Ohio, N. America. 



The coloured epidermis is so thin that the crowded 

 tubercles (which are elongated and almost perpendicular 

 near the ridge) often become whitish from abrasion. 

 There are two sets of folds ; those upon the narrow con- 

 cave space adjacent to the ligament are much the smaller. 



