114 



THE NAUTILUS. 



bridge at Arkadelphia; also Caddo River near County bridge 

 five miles North of Arkadelphia. 



Lymn&a hwnilis modicella Say. Found in the environs of 

 Arkadelphia; in Mill Creek; rarely in the Ouachita River mar- 

 gins. Rare! 



Planorbis trivolvis Say. Ouachita River, Old River, and Big 

 Deceiper Lake, nine miles south of Arkadelphia. 



Planorbis dilatatus Gould. Ouachita and Old Rivers. There 

 are possibly two forms in this lot. 



Planorbis sampsoni (Ancey). Clear Lake, two miles east of 

 Arkadelphia, and ponds south of Arkadelphia (young shells 

 only). This species seems to be exceedingly perishable. 



Ancylus kirklandi Walker. Caddo River (common) Clear 

 Lake. 



Ancylus valkeri Pilsbry and Ferriss. Ouachita River at Ark- 

 adelphia. Very rare. 



Ancylus sp.f Ouachita River near Arkadelphia. 



Physa anatina Lea. Mill Creek, ponds south of Arkadelphia, 

 and Big Deceiper Creek at Gum Springs, six miles south of 

 Arkadelphia. 



Physa sp. ? Clear Lake east of Arkadelphia. 



Strobilops labyrinthica (Say). Arkadelphia. Everywhere 

 common in suitable localities. 



Strobilops labyrinthica texasiana Pilsbry and Ferriss. Arkadel- 

 phia. Not uncommonly there is found what seems to be a 

 hybrid between this variety and the species proper. 



Strobilops virgo (Pils). Arkadelphia, but found also in the 

 bordering county of Grant. 



Pupoides marginatum (Say). Arkadelphia. 



Gastrocopta contracta (Say). Arkadelphia. 



Gastrocopta contracta climeana Van. Arkadelphia, very rare. 



Gastrocopta pmtodon (Say). Arkadelphia. 



Gastrocopta tappaniana (C. B. Ads). Arkadelphia. Col- 

 lected also in adjacent counties north and east of Clark. 



Succinea avara Say. Environs of Arkadelphia, not common. 



Omphalina friabilis (W. G. Binn. ). Arkadelphia. Very 

 rare ! 



Vitrea indentata (Say). Arkadelphia ; Gurdon. 



