ABSTRACT 



Algal Cave (=West Tunnel Cave) in the McDonald Creek drainage of Glacier National 

 Park was visited in September 1999 to confirm the presence of cave isopods that had been 

 reported in the cave in 1998, and to collect vouchers if the isopods were observed. Several 

 aquatic cave invertebrates were reported and collected in the cave in 1977, but apparently these 

 had never been identified, and location of specimens was uncertain. 



Six "pools" in the cave were checked for the presence of invertebrates during the 

 September 1999 trip. White isopods were found in all of the pools, estimated number of 

 individuals in these pools was > 800. In addition, a species of aquatic amphipod, at least one 

 species of planaria, and one species of oligochaete worm were present. Vouchers of each species 

 were collected for later determination by experts. The isopod was identified as Salmaselhis 

 sieganuthrix, the amphipod was identified as a new and as yet undescribed species of 

 Stygubronuis (to be named "^glacialis"), the planaria were not identifiable because of the 

 preservation technique. To date, the oligochaete worm has been identified to the family 

 Lumbriculidae. The aquatic community of cave invertebrates in Algal Cave is the first described 

 for Montana, a similar community may be present in "Zoo Cave", also in the Park, as well as 

 other caves in northwestern Montana with subterranean streams. 



Ill 



