The problem of the differential diagnosis of the strongyloid larvae (filariform stage) of the hookworm of man and of animals is one to which attention must be paid by tropical hygienists all over the world, while it is not possible to seek for larvae of the hookworm of man in polluted soil without a good knowledge of this subject. Also it is desirable that persons who are making researches on this subject be acquainted with the literature hitherto published. The recent researches from the American side of Cobb, of Svensson and of Svensson and Kessel, have attracted attention, but the publications of Dutch authors seem to have slipped out of sight. For this reason I should like to point out this oversight. The author (1924) first questioned the opinion of Looss, that there was no differences between the strongyloid larvae of hookworms of man and of the dog, after Schuurmans Stekhoven-Meyer after a very minute, especially biometrical, examination had expressed shortly before, the wish to join themselves to the opinion of Looss. In that publication the author elucidated by microphotographs (1) the difference in the structure of the chitinous part of the buccal cavity of the larvae of Necator and of Ancylostoma caninur; (2) the much more pronounced transverse striature on the sheath of the first in comparison to the second; this publication is mentioned by Hall in the JOURNAL OF PARASITOLOGY: for 1925, on page 229. In 1926 the author described more minutely the differences between these larvae and especially the structure of the esophagus, the union of esophagus and intestine and of the tail, discussing the recently printed publications of Cobb and of Svensson. The opinion of Cobb was criticised, that the chitinous buccal armature would function as a spear. Since the publications of Svensson and Kessel another one by Schuurmans Stekhoven (1926) has appeared; in this the observations of the author are affirmed in the main; however, as to the strongyloid larvae of Necator and of Anicylostoma caninum, new points of difference are described, and explained by very minute drawings, concerning the excretory apparatus, the presence or absence of lips, the situation of the amphids and of the papillae on the head. Lately in a meeting of the Dutch Society of Tropical Medicine (to be published in the reports of that meeting in the Nederlandsch Tijd-