Mr. C. J. VAN DER HORST has done me the honour to entrust to me for study a very interesting collection of ophiurans, 881 specimens in all, made by himself during April and May, 1920, at Caracas Bay and Spanish Water, Curaçao. Considering the importance of Willemstad as a sea-port and therefore its accessibility, and the cleanliness and healthfulness of the little city, it is curious that heretofore no extensive collections of ophiurans have ever been made there, and such material as has been sent to European museums has remained unrecorded.