UNIO.— Plate LXXXYIII. 



ciinei/ormi, utrinque rotundatd, antiee depressd et con- 

 ce?itrice striata, postice Icsvi et ventricosd, iiiferiie re- 

 tiisii, subviridi-favd, postice obscure radiatd, costd um- 

 bonidi rotundatd; mtibus prominulis ad apices trnns- 

 versiiii uudatis, niargaritd albo-carulescente ; in ntrd- 

 qne valvuld, dente parvo, tuberculiformi, compresso. 



The CoNNASADGi Unio. Shell very thin, bluntly wedge- 

 shaped, rounded at each end, depressed and concen- 

 trically striated in front, smooth and ventricose be- 

 hind, retuse beneath, greenish-yellow, indistinctly 

 rayed posteriorly ; umbonal ridge rounded, beaks ra- 

 ther projecting and with transverse waves at their 

 tips, nacre bluish-white ; a single small compressed 

 tubercle-like tooth in each valve. 



Lea {Margaritana), Obs. on Uuio, vol. vii. (.Journ. Ac. 

 Nat. Sc. Philad. ser. 2. vol. iv.), pi. 32. f. 113. 



Hab. Connasauga river, Georgia, U. S. America. 



When young, the capillary rays extend over the entire 



disk. 



Species 475. (Copied from Lea.) 

 UiNio BTJLLOIDES. Un. testd subteuui, iuflatd, siibcci/ai- 

 laterali, nowiiJdlo rottmdato-subqnadratd, auiice an- 

 gustatd, postice truneatd et superue rectaiii/uhiri, in- 

 ferne arcuatd, Inteo-fuscd concolore, concentrice cou- 

 fertim sulcatd, costd mnbonali rotundatd et elemdd, 

 lunuld rmlld, ared dorsali posticd latd ; umbonibus 

 prominulis, porcis radiantibus jiarvis ornatis ; niarga- 

 ritd albd; dentibus cardinalibus pralongis, lamellatis, 

 valde obliquis ,• dentibus lateralibm subrectis. 

 The stud-like Unio. Shell thinnish, inflated, subequi- 

 lateral, of a somewhat rotundately squarish form, but 

 naiTOwed in front ; truncated and rectangular above 

 posteriorly, arcuated at the ventral margin, of a uni- 

 form yellow-brown, with close-set concentric fur- 

 rows; umbonal ridge raised and rounded, no lunule, 



hinder dorsal area broad, umboes rather promiuciil 

 and adorned with radiating ridges, nacre whit(> ; 

 primary teeth very long, lamellar, very oblique ; la- 

 teral teeth straightish. 

 Lea, Obs. on Unio, vol. vii. (Journ. Ac. Nat. Sc. Philad. 



ser. 2. vol. iv.), p. S3, pi. 42. f. 144. 

 Hub. llio de la Plata, S. America. 



Lea, who described this i-are shell from a single speci- 

 men, remarks that in outline it approaches U. Faranmsis. 



Species 476. (Copied from Lea.) 



Unio spissus. Un. testd crassd, ventricosd (antiee autem 

 depressd), subaquilalerali, subelliplicd, postice obtuse 

 biangulatd, fusco-rufescente, obscure radiatd, in/erne 

 concentrice striatd (vel sulcatd), superne nitidd Irevi- 

 que, costd umbonali valde elevatd et obtuse angulatd, 

 ared posticd, dorsali latissimd, rude striatd et bipor- 

 catd, lunuld angustd, margaritd scepius purptired (ali- 

 quando autem pallide rubro-aurantid) ; dentibus car- 

 dinalibus inagnis, erectis, compressis, crenulatis ; den- 

 tibus lateralibiis percrassis, elongatis, subarcuatis. 



The compact Unio. Shell thick, ventricose (but de- 

 pressed in front), subequilateral, subelliptic, bluntly 

 biangulated behind, reddish-brown, obscurely rayed, 

 striated or grooved concentricaUy below, shining and 

 smooth above ; umbonal ridge much elevated and 

 bluntly angidar, hinder dorsal area very broad, coarsely 

 striated and double-ridged, lunule narrow, nacre usu- 

 ally purple (sometimes salmon-coloured); primary 

 teeth big, erect, compressed, crenulated ; lateral teeth 

 long, very thick, somewhat curved. 



Lea, Obs. on Unio, vol. vii. (Journ. Ac. Nat. Sc. Philad. 

 ser. 2. vol. iv.), p. 26. pi. 25. f. 89. 



Ilab. Satilla river, Georgia, America. 



Allied to Lecontianus, but less transverse. 



