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low thorny shrubs, and to the West Indian birch (Bursera). Tall 

 tree-like prickly pears {Opuntia) are the most conspicuous cac- 

 tuses, often forming groves. The few short rivers across this dry 

 country seem to be utilized to their full capacity for the irrigation 

 of the cane fields which occupy the more level portion of the val- 

 leys and the coastal plain. 



The two detachments of our expedition joined forces at Arecibo 

 on the north side of the island, March 13, the Culebra party 

 coming from San Juan by rail, the Mayaguez party coming across 

 the island from Ponce by carriage, and making considerable col- 

 lections along the way. We all proceeded the next day to our 

 third objective point, Utuado, a point situated among the moun- 

 tains of west-central Porto Rico, and this point was made a base 

 of operations for a week. The drive from Arecibo to Utuado is 



