Epiperipatus biolleyi and Epiperipatus isthmicola from Costa Rica were studied in the laboratory. Morphometric analyses of E. biolleyi show that: (1) larger animals have more legs and (2) females have 8 % more pairs of legs, and axe 24 % longer and 50 % heavier than males. An estimation of how alcohol preservation affects body length indicates less shrinkage in females. Physiological observations on E. isthmicola showed that (1) n a session these animals can lose a mean of 7.4 % of body weight (SW) by expelling shear adhesive secretion, (2) weight loss by water evaporation was in average 2 % of BW/min at 66 % relative humidity, and (3) larger animals lose water more slowly. A parturition of E. isthmicola was typical of the family
