A collection of 79 specimens of Notostraca from the islands of Bonaire, Curaçao, and Aruba was kindly handed over to me for examination by Dr. P. WAGENAAR HUMMELINCK, Utrecht, to whom my thanks are due for giving me this opportunity of seeing some interesting material. All the specimens concerned belong to Triops longicaudatus (LeConte) — usually known as Apus longicaudatus LeConte — which is the only species of its genus yet found in America.