140 TIIE NAUTILUS. 



Valley Head, Ala., 1.55 x .65 mm. 



Lemon City, Fla., 1.G0 x .70 mm. 



Staten Island, N. Y., 1.65 x .75 mm. 



Edgewortli, Pa., 1.70 x .75 mm. 



Des Moines, Iowa, 1.85 x .75 mm. 



Iowa City, Iowa, 1.80x.70 mm. 



Crooked Lake, Emmet Co., Mich., 1.75 to 1.85 mm. 



Kennebunkport, Me., 1.85 x .80 mm. 



Pigeon Lake, Ont., Can., 1.90 x .80 mm. 



Orono, Me., 1.80 to 1.90 mm. 



Ann Arbor, Mich., 1.65 to 2.00 mm. 



Huron Mtn., Marquette Co., Mich., 2.15 x .85 mm. 



These figures seem to indicate an increase in size in the north, but 

 the Ann Arbor lot shows almost as much variation as in the balance 

 of the range. The Huron Mountain shells are unusually large, much 

 larger in fact than any others seen from Michigan, and their size is 

 probably due to favorable environment as in other parts of the state 

 typical shells are found. 



EXPLANATION OF PLATE VIII. 



Fig. 1. Carychium exile canadense n. v., Kennebunkport, Me., 

 2.1 x .75 mm. 



Fig. 2. Carychium exile canadense n. v., Winnipeg, Manitoba, 

 2.05 x .75 mm. 



Fig. 3. Carychium exile Lea, topotype, Wissahickon Cr., Phila., 

 Pa., 1.70 x. 60 mm. 



Fig. 4. Carychium exile Lea, Mt. Vernon, Va., 1.50 x .55 mm. 



Fig. 5. Carychium exile Lea, Edgeworth, Pa., 1.75 x .60 mm. 



Fig. 6. Carychium exile canadense n. v., Ottawa, Ont., Can., 

 2.10 x .65 mm. 



Fig. 7. Carychium exile canadense n. v., Huron Mtn., Marquette 

 Co., Mich., 2.05 x. 75 mm. 



Fig. 8. Carychium exiguum Say, Huron Mtn., Marquette Co., 

 Mich., 2.15 x .85 mm. 



Fig. 9. Carychium exiguum Say, Valley Head, Ala., 1.55x.65 mm. 



Fig. 10. Carychium stygium Call, cotype, Mammoth Cave, Ky., 

 2.00 x. 85 mm. 



