116 THE NAUTILUS. 
15, alt. ataperture 7} mm. Specimens from East branch of Salmom 
brook, Woodland, Aroostook Co., Me., coll. by O. A. Nylander, 
Caribou, Maine. 
Vivipara georgiana limnothauma n. var. 
Whorls much swollen around the upper part, sloping below, giv- 
ing a shouldered appearance. ‘This is one of the most remarkable 
forms of Vivipara yet made known. Types are from an aboriginal 
shell-field on Hitchen’s Creek, but it also occurs living in Lake 
George, 2 fms., off Drayton’s Island (Pilsbry and Johnson coll.). 
MOLLUSKS OF ALLEGHENY C0O., PENNSYLVANIA. 
BY GEO. H. CLAPP, PITTSBURGH, PA. 
Below is given a list of additional species of land and fresh-water 
shells collected in Allegheny Co., Pa., to be added to the list pub- 
lished by Mr. S. H. Stupakoff in the Nauriius, April, 1894. 
Hyalina cellarius Mull. Unio erassidens Lam. 
Hyalina nitidus Mill. Unio luteolus Lam. 
Mesodon mitchelliana Lea. Unio gracilis Lam. 
Pupa curvidens Gld. Unio rubiginosus Lea. 
Suecinea aurea Lea. Unio orbiculatus Hild. 
Succinea obliqua Say. Unio securis Lea. 
Limneea parva Lea. Unio cornutus Bar. 
Gyraulus dilatatus Gld. Unio undulatus Bar. (?) dead 
Pleurocera canaliculatum Say. [broken shell. 
Goniobasis ? (Young). Unio obliquus Lam. 
Unio ovatus Say. Ancylus tardus Say. 
Unio rectus Lam. Ancylus rivularis Say. 
Unio pilaris Lea. 
From the previous list, Mesomphix levigatus Pfr. should be drop- 
I } 9 
ped. I have found Mesodon sayii Binn. in Beaver Co., but have 
not, so far, found it in this county. 
NOTE ON UNIO OREGONENSES LEA. 
For years I have been puzzled over a shell in the Lea collection 
of Naiads which Lea received from Wheatley as coming from the 
