Shell diameter: Discus brunsoni averaged 9.5 mm diameter and ranged from 6.7-10.5 mm (Table 

 1). For Oreohelix elrodi at Site 1, 28 (71.8%) of 39 live individuals were > 15 mm diameter. At 

 Sites 2 and 3 the respective numbers of live snails in this category were 6 (33.3%) of 18, and 2 

 (28.6%) of 7. Samples undoubtedly contained members of more than one cohort. The presence 

 of individuals < 7.5 mm diameter in each sample suggests reproduction is occurring at each site. 

 Oreohelix alpina 



Presence at different sites and substrate selection: Weather on East St. Marys Peak was clear 

 and cool (12.5°C at the summit) on 27 August. I found no snails in 30 min (12:15-12:45) at Site 1 

 on the southeast ridge. 



At Site 2 I found 16 live O. alpina in 45 min (13:30-14:15) in three areas searched along 

 300 m of ridge. All live snails were under limestone blocks about 20 X 30 cm square and 4-8 cm 

 thick. Six snails were attached to the undersides of limestone fragments or atop bare rock 

 beneath overlying blocks, one group of 10 live snails was found in leaf litter (area = 9 cm*) 

 accumulated near the base of snow cinquefoil. Some soil development was present at each site 

 where live snails were found. Dead shells were found with little effort on open ground. 



I searched the summit area (Site 3) for 15 min (14:30-14:45) and found one live snail at 

 2865 m near the top of the southwest ridge. This individual was on bare rock under a limestone 

 block near a patch of snow cinquefoil. 



Shell diameter: Mean (+ SD) diameter of live shells (n = 16) was 5.7 + 1 .9 mm; range was 2.5- 

 8.5 mm. The smaller individuals indicate reproduction is probably occurring at this location. 

 Mean diameter of dead shells for which measurements were possible (n = 9) was 8.9 + 0.5 mm; 

 range was 8.0-9.6 mm. 



8 



