Art. IV. — On the Batrachia and Reptilia of Costa Rica. 



By E. D. Cope. 



Costa Kica, the most southern of the states of Central America, lies between 

 eight and eleven degrees of north latitude, and presents great inequalities of surface. 

 Its length is traversed from northwest to southeast by the range of the Cordilleras, 

 which rise in their highest point, the Pico Blanco, in the southern part of the 

 republic, to an elevation of 11,800 feet. In the middle of the country the range 

 forms the western border of a plateau whose elevation is about 5000 feet, and 

 whose eastern rim is marked by a chain of volcanoes. The principal rivers of the 

 country, which flow into both oceans, take their rise in this plateau. Here also 

 the more important part of the population dwells in the two towns of San Jose 

 and Cartago. 



The climates of the eastern and western regions present material differences. 

 The eastern slope of the country receives the trade- winds loaded with the moisture 

 and clouds derived from the evaporation of the Caribbean Sea under a tropical sun. 

 Constant rain falls on the mountain sides, and the rivers flowing into the Caribbean 

 Sea are remarkable for the volume of water they contain as compared with the 

 length of their courses. The climate of the country west of the mountains is 

 much drier, but not so much so as to constitute aridity. The entire republic, but 

 especially the eastern region, is covered with a dense tropical vegetation. 



Dr. Wm. M. Gabb, from whose explorations much of my information is derived, 

 has discovered that the major part of the rocks of the country are of miocene age, 

 and that the elevation of the Cordilleras took place after the close of that period of 

 geologic time. The volcanoes bounding the plateau on the east are of later age. 



The material on which the present investigations are based consists chiefly of 

 two collections. One made by Dr. Van Patten of San Jose was derived from the 

 country in the neighborhood of that city. The larger collection, made by Dr. 

 Wm. M. Gabb of Philadelphia, under the auspices of the government of Costa 

 Rica, was obtained in the southern portion of the region of Costa Rica which lies 

 east of the elevated mountain range which traverses that country, and at different 

 elevations on the range itself. According to Mr. Gabb, the most elevated point, 

 the Pico Blanco, in the southern part of the State, rises to the height of 11,800 

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