Green, H. 1982 12 March (continued) on a closer look), saw that all the surrounding "ground" was loose mud, and abandoned the snake. It was probably the most "calmly aggressive" and by far the fastest viper I've ever encountered. I didn't feel scared during the whole thing, but during supper and for a couple of hours later, I felt pretty weird about being stuck in the mud near that snake. 13 March out to Arbolin by 0700 w/ Manuel Santana to look for my radio-tagged Chironius. Got the signal right away, along the Quebrada El Surá, but spent 2 hrs. futilely searching the banks and heavy understory for it. Then ~0930 saw it on a small tree limb directly over the creek, ~10m up. Watched it move across the limb, down a vine thins then it, and down into brush. (see separate notes.) ~1400 Dave and Debza Clark brought in an Oxybelis aeneus adult from near the AC lab. It muscled heavily as I palpated a juvenile Ameiva festiva (Head-first swallowed) from its stomach. Also saped, hung limp, and then bit vigorously on my parts when hung free from my hand.