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NORTH AMERICAN FAUNA. 



they were apparently ratlier comnion about the wild fig trees in the 

 forest and were feeding upon the figs. They may occur also on the 

 other islands, especially uj)on Maria Magdalena. Two men living on 

 the island described the nests of these animals as globular masses of 

 dry leaves and small plant stems, lined with shreds of softer vegetable 

 matter. The nests are built in the forks of bushes, from 3 to 8 feet 

 from the ground, and have the entrance on the lower side. One of 

 the men found a nest situated as described and about 3 feet from 

 the ground. He saw the owner peering out of a hole near the lower 

 side, but as he approached the head vanished, and the entrance was 

 suddenly closed by the opossum drawing some of the nest material 

 across it. The nest was quickly thrust into a game bag, and when 

 examined was found to contain a female opossum and a number of 

 young clinging to her fur with their feet and tails twined closely 

 about hers. The weight of the young was so great that the ijarent 

 could only walk very slowly. 



Oryzomys nelsoni Merriam. Nelson's Rice Rat. 



Oryzomys nelsoni Merriam. Proc. Biol. Soc. Washington, XII, p. 15, Jan. 27, 

 1898. Type from Maria Madre Island. 



This rice rat is probably a rare species, as only a few specimens were 

 secured after much trapping. They were found only in damp places 

 near springs about the summit of Maria Madre, about 1,800 feet above 

 sea level. This seemed the most suitable location for them on account 

 of the juicy herbaceous vegetation mingled with the undergrowth. 



Peromyscus madreusis Merriam. Tres Marias Mouse. 



Feromyscus madrensis Merriam. Proc. Biol. Soc. Washington, XII, p. 16, Jan. 27, 

 1898. Type from Maria Madre Island. 



This is the mostly widely distributed and probably the most numer- 

 ous rodent. Specimens Avere taken on the three large islands, but 

 its occurrence on San Juauito, where land crabs are very numerous, 

 is doubtful. They were generally distributed over the forest-grown 

 slopes bordering the shore, above the belt infested by crabs. On 

 Maria Madre they were most common about the wild fig trees near the 

 summit (1,500 to 1,800 feet), where the pigmy opossums were secured. 

 Here their burrows entered the ground under logs or projecting roots, 

 but elsewhere these mice were found living beneath rocks and small 

 ledges. They are apparently restricted to the forest, and while 

 nowhere so abundant as were the rabbits in one place near the north 

 end of Maria Madre, yet they were much more generally distributed. 



Mus rattus Linn. Black Rat. 



These rats were found in small numbers about the houses and dis- 

 tributed over the forested parts of Maria Madre and, as on the main- 

 land of western Mexico, we found only the gray form. 



Lepus graysoni Allen. Tres Marias Cottontail. 



Lepus graysoni Allen, Mon. N. Am. Rodentia, pp. 347-348, 1877. Type from Tres 

 Marias Islands (undouLtedly from Maria Madre). 



The cottontail is abundant in some places on San Juanito, Maria 

 Madre and Maria Magdalena, and was reported to occur on Maria 



