Two species of leeches only have been collected by dr HUMMELINCK in 1936—1937, but these are important as they evidently prove the occurrence in warm tropical waters of species hitherto only recorded from non-tropical areas. Helobdella scutifera is distinguished from H. stagnalis by AUTRUM, 1936, p. 26 and 34, though PAWLOWSKY (cf. AUTRUM 1939, Bronns Kl. u. Ordn., Hirudineae 2, p. 500) considered them synonymous. AUTRUM (l. c. p. 500 and footnote) remarks that H. stagnalis is not known from tropical localities, supposing the habitats in Ecuador, Brasil and Paraguay perhaps to be non-tropical because of their particular position. Our material, however, shows affinities to both species and tends to affirm the identity of H. stagnalis and H. scutifera. It is important to know that our habitat was really tropical, the temperature measured being 28°—31° C.