246 A YEAR OF COSTA RICAN NATURAL HISTORY 



fessor Tristan, who had been to the top, told me that the 

 ascent must be made by one of these canons, whose steep- 

 ness adds much to the difficulty of the climb, and that some 

 sulphurous vapors are still given oflf by the volcano. Two 

 eruptions of Turrialba volcano are known. One lasted 

 from August 17, 1864, to the middle of March, 1865; during 

 part of this time there fell a rain of very fine ashes and dust 

 in the valleys of Cartago and San Jose, carried thence by 

 the prevailing winds. The second and at times more violent 

 eruption began February i, 1866, and was accompanied by 

 earthquakes which, on May 8, were felt at San Jose; the 

 column of ashes reached to Puntarenas, a distance of seventy 

 miles in a straight line. 



On July 24 we crossed the Rio Turrialba on the railroad 

 bridge and walked for a mile or so through a potrero dotted 

 with trees, a coffee-plantation, and a second similar potrero, 

 all bordering the eastern bank of the river; we searched par- 

 ticularly under logs, beneath the bark of decaying trees and 

 in the sheathing bases of the leaves of bromeliads growing 

 upon trees for earwigs, spiders and earthworms. During 

 the course of our stay at Turrialba we found a number of 

 these last in bromeliads seven feet or more above the ground; 

 Professor Tristan supposes that the egg-cases have been 

 brought by birds in the earth on their claws and accidentally 

 dropped so as to enable the worm to develop occasionally 

 in these plants. 



To me the most interesting find of the afternoon was one 

 of the animals known as Peripatus, a form intermediate in 

 many respects between the earthworm group on the one 

 hand and the centipede group on the other. Peripatus and 

 its immediate allies to the number of fifty species, known 

 collectively as the Onychophora, are found only in the warm 

 regions of the earth — South Africa, Malacca, Sumatra, 

 Australia, New Zealand, South and Central America, Mex- 



