THE NAUTILUS. 17 



H. viultillneata unicolor. Cited by Currier and De Camp. 



H. thyroides Say. Common throughout the state. 



H. thyroides buccnlenta Gld. Cited by De Camp. 



H. albolabris Say. Common everywhere. 



S. albolabris dentata. Occurs occasionally with the type. 



H. albolabris martivia Pils. Traverse City. Specimens of tliis 

 well marked form were sent to me by Dr. M. L. Leach, which 

 appear to be identical with examples from New Jersey. It has 

 been persistent in its present form for ages, as it is found unchaiiged 

 in the marl-beds upon which the living specimens were found. Di-. 

 Leach thus describes the habitat of the species : " The locality is 

 limited, containing only a few acres on and around the marl-bed 

 where their remaius in connection with fluviatile shells are found in 

 a fossil condition. I find only now and then one of the same 

 variety anywhere else and that always not far away." 



A single specimen collected by Dr. Leach at Black Lake, Presque 

 Isle county, is probably referable to the same variety. This would 

 indicate a range across the entire northern part of the lower 

 peninsula. 



H. exoleta Binn. Common in the southern part of the state. 



H. elevata Say. Rare, if found at all in the state. The Grand 

 Rapids collectors have not found it, nor have I. Cited by Sagar 

 and Miles whose citations are followed in later catalogues. It 

 occurs in recent deposits near Ann Arbor, but is now extinct there. 



H. profunda Say. Occurs commonly through the southern part 

 of the state. 



H. profunda alba. Occasionally associated with the type. 



H. saijii Binn. Cited in most of the catalogues but appears to 

 be rare and confined to the northern part of the state. Black Lake, 

 Presque Isle County, where it was collected by Dr. Leach, is the 

 only locality I know of. 



H. hirsuta Say. Common everywhere. 



H. monodon Rack. Common everywhere. 



H. monodon fraterna Say. Not as common as the type. 



H. leaii Ward. Southern part of the state, common. 



H. tridentata Say. Appears to be generally distributed through 

 the state as it is cited in all catalogues. 



H. fallax Say. More abundant than ^?-(de/i^a^a, judging from my 

 own experience. 



