IJA- 10.— Plate LXV. 



Species 331. (Mus. Taylor.) 

 Umi) TRIUOSTIUS. Un. testa obloiigo-siihordtn, suLioUJii, 

 Immdd, angustd, lavi(jala, iiitus aWn ; hdrre /jostico 

 prodiwto, obscure biaugulato, margine dorsali recto, | 

 lalmili perolliqito, termino inter angulos truiwatu, < 

 margine venlrali ad terminum aursuiii acrlivi, post me- 

 diiii.i Infiatd, medio vix confracto, iimhoiiihus siibpro- ! 

 M'nieiitibiis, coslellis graniferis, nngularUi-r dicergenli- | 

 hns riigata ; latere anlico subrotiuido. 

 The trirostral Unio. Shell obloiig-subovate, raUicr 

 solid, tumid, narrow, smooth, white within; posterior 

 -side ])rodnced, obscurely biangular, dorsal margin j 

 straight, lateral very oblique, end between the angles ' 

 truneatetl, ventral margin sloped upwards at the end, \ 

 inrtatcd behind the centre, very slightly contracted in 

 I he middle, umboes rather prominent, wrinkled with 

 grannlo^c angularly diverging ribs; anterior side 

 rather round. ; 



UbNsON. j 



Uah. India. 



\ cry much longer than U. creriitea, anil a more solid 



Species 332. (Mus. Taylor.) 

 > KECTILI.NEARIS. Utt.tesld oiilougd, angmtd, tiihiidii, 

 SI ill :hl. I, t ri If, 1 1 J.fiisco-viridesceHti, intiin salmoned et cae- 

 i-iiirii.iii,iliiiiiiiiiix n(gosis,costellislubercuUfiri^angulatis 

 (iniutis ; latere pustico biangulato, margine dorsali con- 

 rexo, laterali declioi, termino inter angulos truncato, 

 area postangulari oblique rugatd, margine venlrali 

 redo ; latere anlico proiJticlo, margine dorsali ante 

 umbones excaoato. 



The rectilinear Unio. Shell oblong, narrow, tumid, 

 solid, smooth, brownish -green, salmon-tinted and 

 liluish within, umboes rugose, ornamented with an- 

 gular tuberculiferous riblets ; posterior side biangular, 

 dorsal margin conve.x, lateral sloped, end truncated 

 between the angles, postangular area obliquely 

 wrinkled, ventral margin straight; anterior side pro- 

 duced, dorsal margin excavated in front of the 

 umboes. 



SOWERBY. 



llab. Kiver Columbia. 



Species 333. (Mus. Taylor.) 



IMo uiGiTlFORMls. Uh. testd angustd, elongaid, inmi- 

 (lissimd. crassisiimd, epidermide nigra tavigaid indutd, 

 ii/liis alba, ilrnlibidi anlicis magnis, laceratis, posticis 

 laminatis elongali\ ; latere postico oblique, angulalu, 

 ad terminum aiiguli acuniinalo; margine venlrali pnstice 

 sHJjinflato, contraclo, medio n-rlu ; liilere anlico bre- 

 viisimo, uu/bonibus magnis. 



The FINGER-SHAPED Unio. Shell narrow, elongated, 

 very tumid, very thick, covered with a black, smooth 

 epidermis, white within, anterior teeth large, jagged, 

 posterior teeth laminar, elongated ; posterior side 

 oblique, angular, acuminated at the end of the angle, 

 ventral margin slightly swelled posteriorly, then con- 

 tracted, straight m the middle; anterior side very 

 short, umboes large. 



SoWKKBV. 



JJab. India. 



Slightly resembling U. Shepphardianus in general form, 

 but verv much shorter, and more tumid and thick. 



