51 



being found in Brasil, British Guyana, Jamaica, Martinique, Maur- 

 itius, Singapore, Java, Sumatra, Nias, Celebes (Weber) and Queensland. 



8. Pontoscolex corethrurus F. Müller. 

 Java: Buitenzorg, very common. 

 Sumatra: Padang, Singkarah, Manindjau, Pajakombo, Kaju- 



tanam, a great number of young specimens, under dead wood. 

 Celebes: near Makassar, several specimens in freshwater. 



In a critical paper on the systematical characters of P. corethrurus 

 Rosa ') has tried to demonstrate , that all the specimens of the above- 

 named different countries probably belong to the same species, and 

 that the differences in characters, mentioned for some of them, have 

 no value, because they are based upon a different manner of enume- 

 ration of the segments. With regard to U. dubia from Sumatra 2 ), 

 described by my-self, I am quite prepared to agree with Dr. Rosa's 

 opinion; the specimens at my disposal were in a very poor state of 

 preservation and therefore the buccal-segment seems to have been over- 

 looked. As to the specimens examined by Perrier, which came from 

 different regions (Java, Martinique, Brasil) there still rests with me 

 some doubt, whether they all are referable to one and the same species. 



In all our specimens (a rather large number) the setae of the ven- 

 tral couples commence to diverge in segment XI (Xth setigerous), 

 the external of them (2) moving dorsally; the setae of the dorsal 

 couples usually diverge in segment XII, in some individuals how- 

 ever upon segment XI or XIII, the divergence being not always 

 symmetrical. Behind the clitellum the setae begin to alternate in 

 position, the dorsal ones first, those of the ventral couples upon seg- 

 ment XXVIII or XXIX. The internal setae of the ventral couples (1), 

 in the succeeding segments of a great portion of the body, remain 

 situated in the same line. 



In the specimens , examined by Perrier 3 ), the superior setae 

 of the dorsal couples commence, according to his description, to be 

 displaced on segment XIII (XIV Perrier) and the external ventral 

 ones not before segment XXIII (XXIV Perrier); he also found copu- 



1) Anu. del Mus. Civico di Storia Natur, di Genova, Vol. XXVII, 1889, p. 1 



2) Midden-Sumatra, Reizen en onderzoekingen der Sumatra-Expeditie , IV, Zoologie, 

 XII, Vermes, p. 7. 



3) Archives de Zoologie Expérimentale, Vol. XIII, 1874, p. 394. 



