PURINE EXCRETION IN FIVE SCORPIONS, A UROPYGID AND A CENTIPEDE

¹ Department of Biology, Southwest Texas State College, San Marcos, Texas 78666

1. Effects of diet on uric acid excretion of three scorpions, Centruroides vittatus, Vejovis mexicanus and Vejovis sp., and the vinegarroon, Mastigoproctus giganteus, have been investigated. Uric acid probably is not a normal end product of nitrogen catabolism, except possibly in C. vittatus. Yet even here the pattern is inconsistent. Quite likely the uric acid in arachnid excreta is exogenous in origin.

2. The most important nitrogenous waste in these arachnids was guanine. In contrast to other reports on African and Asian scorpions, uric acid and hypoxanthine are of little consequence in the North American species.

3. In the large Thai scorpion, Heterometrus sp., the malpighian tubules are of lesser importance in guanine excretion than the mesenteron. Apparently guanine is synthesized in the mesenteron and passes via the diverticula into the gut canal rather than being excreted by the malpighian tubules.

4. Considerable quantities of uric acid are excreted in the centipede, Scolopendra heros, probably via the malpighian tubules.