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NATURALIST'S GUIDE TO THE AMERICAS 



number and in proportions, and one finds 

 a good carpet of grass with xerophytic 

 annuals replacing the scrub under- 

 growth. 



This region marks the western limit 

 in Texas of the Virginia deer, but the 

 species is not abundant in the savanna. 

 The prairie spotted skunk {Spilogale 

 interrupta) comes into Texas from the 

 savanna to the north and it is found 

 pushing its way westward into the grass- 

 lands where local conditions of countrj^ 

 and vegetation permit. Here also ends 

 the range of several cottontail rabbits, 

 the raccoon (following up local aspects 

 of the heavier forest regions) and the 

 squirrels, previously mentioned, of the 

 Atlantic woodlands. One animal can 

 be cited as characteristic of that part 

 of the oak grove savanna which we 

 have mentioned as being cut off by the 

 deciduous forest. In that portion of the 

 savanna lying along the coast we find 

 the gulf spotted skunk (Spilogale india- 

 nola) whose range is entirely within 

 the savanna, being cut off and isolated 

 here by the heavy timber to the north 

 and the mesquite semi-desert to the 

 south. 



4. Coastal Prairie 



This is a relatively narrow band of 

 territory projecting southward along the 

 coast of Texas, wedging itself in between 

 the coniferous forest and the Gulf of 

 Mexico. Geologically, it is new land. 

 It is the westward extension of the region 

 of the Mississippi delta, and reaches 

 southwestward into Texas approxi- 

 mately to Matagorda Bay and the mouth 

 of the San Antonio River. It is a region 

 of little drainage and considerable rain- 

 fall (from 35 to 50 in.) and is so low that a 

 considerable part of it is practically a 

 brackish water meadow. Along the 

 coastline itself this merges into marsh 

 conditions, which are scattered all along 

 the gulf. The region is practically tree- 

 less except for a narrow strip of transi- 

 tion between the prairies and the forest 

 to the north and west, and is character- 

 ized by the presence of a rich, grassy 



vegetation composed of moisture-loving 

 species. This is particularly true over 

 the eastern two-thirds of the area, where 

 the rainfall is in excess of 40 in., while 

 the western third is marked by the 

 dominance of species demanding less 

 moisture as the area pushes southward 

 toward the semi-desert country. The 

 dominant species are the water grasses, 

 broom sedges (Andropogon spp.) panic 

 grasses and emersed aquatic plants. 

 Marsh grass (Spartinasp.) is abundant, 

 as is, locally, the dropseed (Sporobolus 

 sp.). 



It is not surprising to find within this 



isolated and cut off region a number of 



species of animals whose range does not 



extend beyond the very limited confines 



of this highly differentiated area. The 



Florida opossum (Didelphis virginiana 



pigra) is typical of the region, and is 



closely confined to it. It is unknown 



south of Matagorda Bay, and its range 



extends north and east following the 



coastal prairies along the coast. The 



small mouse {Peromyscus taijlorx subater) 



a very dark race, is confined to the dry 



coastal prairies north of Matagorda 



Bay, and is unknown from any other 



region. Here it lives under the rich 



carpet of grasses in the open country, 



with habits that remind one of those of 



a meadow vole (Microtus) . Associated 



with it is the Louisiana vole {Microtus 



ludovicianus), also confined to the dry 



prairies. The rice rat {Oryzomys palus- 



tris texensis) is confined to the marshes 



of the coast region, and is very common 



throughout the wet areas, as is the 



swamp woodrat {Neotoma floridana 



rtibida) whose range, however, has an 



extension northward into the "big 



thicket" of Hardin County. Closely 



confined to these marshes one finds also 



the coast swamp rabbit {Sylvilagtis 



aquations litllralis) which extend out 



only to enter the big thicket where local 



conditions are similar to those of the 



coastal marshes. The typical swamp 



rabbit {S. a. aquaticus) inhabit the 



bottomlands of all streams of eastern 



Texas. 



