Micoureus cinereus paraguayanus (Tate, 1931) is cited to Rio Grande do Sul State, Brazil for the first time. There is a description of the marsupial, measures of body and skull, drawings of skull and teeth and geographic distribution maps.

Study of 179 specimens of Molossus molossus in Ceará, Brazil, showed morphological and functional ovarian asymmetry in adult females, with the right side more developed. Blastocyst implantation occurred also in the right uterine horn. Active male testicles were bigger (x = 5,38mm) than inactive ones (x = 3,25mm). Pregnancy with subsequent offspring was found in March-April and November, during the wet season.

The genus Holochilus Brandt, 1835 is represented in Rio Grande do Sul, Southern Brazil, by two forms: H. brasiliensis vulpinus (Brants, 1827) e H. magnus Hershkovitz, 1955. They are myomorph rodents with semi-aquatic habits. Species of Holochilus range from Northern South America to Central Argentina. In this paper, I present an analysis of standard measurements of specimens collected in Southern Brazil and deposited in the collections of FZB, PUC and UFRGS and a distribution map with collecting localities.