MFSmith 1993 JOURNAL Bariloche, Rio Negro Province, Argentina Sun Nov.21 When I arrived I got settled in an apartment in the building next to the Pearsons, and had dinner at their apartment. This morning we drove towards Cerro Otto, and hiked to the top along a path through Nothofagus beech forest. In a field along the road on the way we had stopped to examine mounds of Ctenomys mandibulines. In the forest we saw evidence of digging and snow cores of Chlamyphorus, especially in patches of wild lilies. From the top of Cerro Otto there is a good panoramic view of the region. Peggy and Anita pointed out several "micro localities" around Bariloche where they have caught either "Akodon" perthorhinus or "Akodon" olivaceus. A. olivaceus is a forest animal extending to the west into Chile, while A. xanthorhinos is a steppe animal extending to the east of Bariloche. We are interested in collecting samples of tissues to be able to do protein electrophoresis as well as DNA sequencing in the region where the two apparently distinct morphological forms come in contact. Some animals appear to be