LYMNZIDZ OF NORTH AMERICA, 439 
one to eight are very uniform in oronensis; the ninth lateral has a 
small indication of an entocone, the tenth and eleventh teeth are typi- 
cal intermediates with well-developed entocone and ectocone; the 
twelfth tooth has usually a bifid entocone, while the thirteenth tooth 
is a normal intermediate. The fourteenth tooth and all which fol- 
lows are typical marginals, with irregularly serrated margin; the meso- 
cone persists in a few marginals, but all of the cusps become sub- 
equal at about the seventeenth tooth. 
GENITALIA: Not examined. 
RANGE: (Figure 49). Maine to eastern Ontario. A species of 
the Canadian and Nova Scotian regions and of the Boreal (Canadian), 

yr Distribution of 
“ts GALBA ORONENSIS 
\\ @ GALBA BINNEYI | 



Transition and Upper Austral life zones; it is confined to the Atlantic 
drainage. 
RECORDS. 
UnITeEp STATEs. 
Maine: Lincoln, Penobscot River, Penobscot Co. (Bost. Soc. N. H.); 
Orono, Penobscot Co. (Bolles; Stearns; Walker) ; Lake Auburn, Androscoggin 
Co. (Lermond) ; Caribou River, Aroostook Co. (Nylander). 
BritisH AMERICA. 
Ontario: Ottawa, Carleton Dist. (Latchford; Heron; Walker). 
GEOLOGICAL DistTRIBUTION: Unknown. 
Ecotocy: Not differentiated from emarginata. 
