MUSSELS OP BIG BUFFALO FORK OF WHITE RIVER. 17 



raised places, hardly pronounced enough to be called pustules, ex- 

 tending ventrad. The species is not nearly so pustulose as C. irrorata. 

 (Lea). The fine tesselated markings, green on a yellowish ground, 

 sometimes disposed in broad rays, are similar to the color markings 

 of the last-named species, and assist in identifying the species. 



It was found at the following stations: 6, scarce; 16, scarce; 19, 

 scarce ; 25, scarce. 



Fantail, THtogonia tuberculata {Bai'nes). — From the place where 

 first encountered, station 8, to station 25 this is a fairly common shell, 

 though rather scarce at some stations. In all, 48 shells were taken. 

 At station 15 it was known as " fantail." The shells are all relatively 

 small and thin, and most of them exhibit the peculiarity of having 

 a purplish nacre, only very few being white, but none so deep a purple 

 as frequently occurs in specimens from Texas. In the Iowa and 

 upper Mississippi Rivers, where this species attains large size and 

 always or most always has a white iridescent nacre, it is valuable for 

 buttons, knife handles, etc., but the thin pui-plish Arkansas shells are 

 of no commercial value. 



It is significant that though the greater number of these shells have 

 colored nacre, Lampsilis Ugamentinus, which is frequently rose 

 tinted in the upper Mississippi, and Quadrula coccinea, which often 

 has rose-tinted nacre everywhere, show little disposition here to 

 develop colored nacre, this in the greater number of cases being white. 

 This shows clearly that the causes producing tinted nacre are not the 

 same for all species, and may be an individual peculiarity. 



It was found at the following stations: 8, scarce; 10, scarce; 14, 

 common; 16, scarce; 17, scarce; 18, scarce; 19, scarce; 20, scarce; 21, 

 scarce ; 22, scarce ; 23, common ; 24, scarce ; 25, common. 



Red shell, Lamjmilis purpuimtus {Lamarck) . — Fairly common from 

 station 14 to station 25, 25 shells having been secured in this portion 

 of the river. They exhibit no variation except, in size. Some of the 

 examples are rather small, but the greater number are of good size. 



The young shells are thin and fragile, but later become thick and 

 heavy. The species closely resembles L. alatus in the color of nacre, 

 which is rich purple, and that of the epidermis, which is black. It 

 differs from that species in being considerably more inflated and 

 with very little wing. The species is rather closely related to L. 

 alatus and is said to have a wedge-shaped glochidium, which would 

 agi-ee with that of alatus. At station 15 it is known as the " red 

 shell." 



It was found at the following stations: 14, scarce; 16, scarce; 18, 

 scarce ; 20, scarce ; 22, common. 



Lamypsilis glmis {Lea). — Only one specimen of this small species 

 was found. It was obtained at station 16. It is inconspicuous both 

 in color and size and is liable to be overlooked even where fairly 

 common. 



9275°— 13 15 



