118 



THE NAUTILUS. 



Lampsilis higginsi (Lea) . A fine typical series of this species 

 was collected from the Ouachita River below Arkadelphia, at 

 Skillern's Shoals, and also in Old River. 



Lamsilis higginsi grandis Simpson. Old River. These shells 

 are larger and less inflated than typical higginsi. The feeble pos- 

 terior ridge, high beaks, shining surface, and the absence of 

 growth ridges make the identification satisfactory. 1 



Lampsilis (Nephronaias) ligamentina (Lam.). Everywhere 

 common in the Ouachita and Old Rivers. The common 

 " mucket" of the pearlers. 



Lampsilis fallasiosa (Smith) Simpson. A common species 

 collected in the Ouachita River, Old River, and Terra Noire 

 Creek. The validity of this species as distinct from anodontoides 

 Lea presents no difficulty to one who has a series of shells from 

 Arkansas localities to compare with those from regions further 

 North. Consult Simpson's diagnosis in his " Descriptive 

 Catalogue. ' ' 



Eurynia recta (Lam.). Ouachita and Old Rivers. 



Eurynia subrostrata (Say). Though not common this species 

 has been found in Ouachita and Old Rivers, Big Deceiper 

 Creek at Gum Springs, Big Deceiper Lake, and a few " sloughs " 

 south of Arkadelphia. 



Micromya lienosa (Con). Ouachita and Old Rivers. Rare. 



Micromya lienosa nigerrima (Lea). Common in both Ouachita 

 and Old Rivers, Big Deceiper Creek at Gum Springs, and 

 Caddo River. The nacre is white, and the epidermis a lead- 

 black, unpolished. 



Eurynia (Micromya) arkansasensis (Lea). On July 28, 1913, 

 two females from the Ouachita River south of Arkadelphia were 

 sent to Dr. Ortmann, who reported: "I think here we have 

 arkansasensis again! These agree rather well with females re- 

 ceived previously (from you) from Saline River, Benton." 

 The species is smaller than lienosa, lighter in color, and with a 

 silvery nacre. Of the arkansasensis collected from the Saline 

 River on July 13, 1911, of which there were four males and 

 two females, Ortmann says: "Here it is! The males, although 



1 See " Descriptive Catalogue of the Naiades," Simpson, p. 78. 



