Our knowledge of the genus Chloeia, though containing Annelids that for the greatest part are obviously coloured and are living in shallow water, is very incomplete; for although about twenty species have been described, it is a fact that more than half this number is insufficiently characterized and based upon badly preserved specimens, having not only lost their distinct colour-markings, but the bristles of which were also disorganized. Although the great Annelidologist Grube in his description of Chl. egena ¹) says: „durch das lange Liegen in Weingeist mögen manche Veränderungen entstanden sein, es ist mir aber nicht wahrscheinlich, dass die dunklen, so bestimmt umschriebenen ansehnlichen Flecken, welche bei Chl. flava auf der Mittellinie des Rückens stehen, spurlos verschwunden sein sollten” etc., yet this really happens. So f. i., in a specimen of Chl. flava in our museum, brought home from Japan by von Siebold, the dorsal spots have totally disappeared and a couple of individuals of Chl. parva, preserved only for a year in formaline, are entirely discoloured and have lost all colourmarkings. Even the bristles, being of calcareous composition, appear to undergo, probably in consequence of the development of traces of acid in the preserving fluid, considerable changes and to lose sometimes entirely their serrulations 1); f. i. in the collections of the Leyden Museum there is a specimen of Chl. flava, from the Port of Singapore, that for some time was preserved in formaline, showing only smooth bristles. Also the Chl. flava mentioned by Quatrefages, characterized „remus superus setis laevibus” 2), can be explained in this manner. Moreover Marenzeller 3) in 1893 fixed the attention thereupon, that the bristles, contained in the anterior body-segments, differ from those of the following ones, and because this character is overlooked in the elder descriptions of the species, „treten die Mängel der bisherigen charakteristik der Chloeia-Arten klar zu tage” (Marenzeller). In the following table those species of Chloeia are enumerated, which appear to me sufficiently described and figured to be recognized.