1892.] NATURAL SCIENCES OF PHILADELPHIA. 131 



NEW AND UNFIGTJRED UNI0NID3:. 

 BY H. A. PILSBRY. 

 Unio Qnintardii Cragin. I'l. Ylf, figs. 1, 2, 3. 



This plicate JJnio presents characters which separate it easily 

 from the numerous Avaved species of the Mississippi basin. The 

 sculpture consists of a series of superimposed Y-shaped waYes, the 

 apices of the V's directed towards the beaks. There are some of 

 the narrow, impressed furrows, crossing the waves at right angles, 

 which form so prominent a character of the sculpture of Uiiio undv- 

 lahis Barnes. The cuticle is dark -brown with occasional blackish 

 streaks, as in other shells of the same group. The beaks are 

 eroded and the nacre white. Other characters are shown in the 

 figure, which is drawn from the original type. 



This species is from Salt Creek, a tributary of the Deep Fork of 

 the Canadian river. Sac and Fox Reservation, Oklahoma Territory. 



A description of this shell was published by Prof. F. W. Cragin, 

 in the Bulletin of the Washburn College Laboratory of Natural 

 History, II, No. 8, p. 6, October, 1887. It has not before been 

 figured. 



Unio Pilsbryi Marsh, Plate YIII, tigs. 7, 8. 



Like the last species, this is a member of the plicate group of 

 L'niones. It is a decidedly compressed, oblong shell, black 

 in color, having very distinctly marked lines of growth, which 

 are spaced over the greater part of the disc, but become 

 crowded on tlie lower margin. It has numerous oblique waves, 

 which generally bifurcate indistinctly toward the posterior- 

 lower end. The waves are more or less cut by short impressed 

 furrows, as in U. undulatus, etc. The nacre is white and very 

 thick anteriorly, but in the cavity of the valves and posteriorly it is 

 thin and stained with blue and olive-green. The lateral teeth are 

 also olive-green. This species was collected by Mr. Elwood Pleas 

 in the Little Red River, Arkansas. It has been described by Mr. 

 Wm. A. Marsh in the " Nautilus, " V. p. 1. 



Unio Pilsbryi is not closely allied to any other American species. 

 It has a striking resemblance to Unio Leai Gray of China. 



Specimens, including the individual figured, are in the exhibit 

 of United States shells in the Museum of the Academy of Natural 

 Sciences of Philadelphia. 



