Veracruzian Biotic Province This Province includes the southern part of the Coastal Plain physiographic region, south of the Sierra de Tamaulipas and Soto la Marina. But the exact line between this Province and the Tamaulipan Province to the north is difficult to draw. The northern boundary of the Veracruzian Province is the line between the Nearctic and Neotropical regions in eastern México. Vegetation of most of the Veracruzian Biotic Province is Tropical Deciduous Forest. This Forest is made up of _Tabebuia_, _Ipomea_, _Bombax_, and _Conzattia_, along with some _Ceiba_, _Bursera_, and _Psidium_. The mammalia fauna of the Veracruzian Biotic Province is tropical in nature. This is especially true of the bats. Representatives of the tropical genera _Micronycteris_, _Sturnira_, _Artibeus_, _Enchistenes_, _Desmodus_, _Diphylla_, and _Molossus_ have their northern distributional limits in this Province. The non-flying mammals characteristic of the Province in Tamaulipas are: _Philander opossum pallidus_; _Marmosa mexicana_; _Ateles geoffroyi velerosus_; _Geomys tropicalis_; _Oryzomys melanotis rostratus_; _O. alfaroi huastecae_; _O. fulvescens engracie_ (endemic to this Province in Tamaulipas); _O. f. fulvescens_; _Reithrodontomys mexicanus_; _Peromyscus orchraventer_ (endemic); _Neotoma micropus angustapalata_; _Eira barbara senex_; _Felis wiedii oaxacensis_; and _Mazama americana temama_. BARRIERS AND ROUTES OF MOVEMENT The distributional patterns and affinities of the mammalian fauna of Tamaulipas suggest possible routes of migration and barriers that limited or controlled movements of the mammals. Mammals may have reached Tamaulipas by way of a Northern route, a Trans-plateau route, a Montane route, or a Tropical route (Fig 3). The Northern route permitted species of mammals from the temperate region to the north to enter the Tamaulipan Biotic Province from or via Texas. Several came from the Great Plains, and a few came from the eastern part of the United States. Also, a few mammals that may have originated in the Tamaulipan Province moved northwards. Some of these, according to Dice (1937:267) were _Liomys irroratus texensis_, _Peromyscus leucopus texensis_, and _Lepus californicus merriami_. Other mammals thought to have moved north by this route are _Didelphis marsupialis_, _Dasypus novemcinctus_, _Oryzomys palustris_, _Nasua narica_, and _Tayassu tajacu_. Some mammals that passed through Tamaulipas into Texas have extended their geographic ranges far north of Texas. Mammals that came _via_ the Trans-plateau route (name proposed by Baker, 1956:146) came no farther into Tamaulipas than the Chihuahuan Biotic Province. They encountered the barrier formed by the Sierra Madre Oriental. These mammals were listed in the account of the Chihuahuan Biotic Province.