DESCRIPTIONS OF GENERA AND SPECIES 333 



Genus Buchholzia, Michaelsbn. 

 Syn. Enehytraeus, Buchholz (in part.). 



Definition. Setae, /-shaped. Head-pore between prostomium and buccal segment ; 

 no dorsal pores. Dorsal vessel arises from the tip of a median dorsal 

 diverticulum of the oesophagus in front of the clitellum ; blood colourless. 

 Salivary glands present. 



This genus was founded by Michaelsen (1, p. 293) for the species termed by 

 Buchholz Enehytraeus appendiculatus. It was defined by Michaelsen in the 

 following words : — ' Enchytraeiden mit farblosem Blut und leicht hakenformig ge- 

 krlimmten Borsten. Die Speicheldriisen sind breit gelappt, mit kurzem Ausfiihrungsgang, 

 und miinden im iv. Segment seitlich in den Oesophagus. Das Gehirn ist im Hinterrande 

 gerade abgestiitzt. Der Giirtel entwickelt sich am viii. Segment und an der vordern 

 Halfte des ix. (schon von Buchholz der Hauptsache nach richtig angegeben). Die 

 Samentrichter liegen vor dem Dissepiment vii/viii, und gehen, dieses Dissepiment 

 durehbohrend, in sehr lange, feine Samenkanale liber. Die Samenkanale miinden 

 im viii. Segment in der ventralen Borstenlinie nach aussen aus. Die Eileiter habe 

 ich nicht erkennen konnen. Die Hoden bilden sich am Dissepiment vi/vii, die Ovarien 

 am Dissepiment vii/viii. Die Samentaschen liegen im v. Segment und miinden in der 

 Intersegmentalfurche iv/v nach aussen.' 



It will be noticed that in this definition the position of the reproductive organs 

 is the main point made use of, while in the generic definition given above the 

 position of these organs is not so much as mentioned. The discovery of a new 

 species of the genus led Michaelsen to abandon the unusual position of the generative 

 organs as a part of the necessary definition of the genus. The new species Buchholzia 

 fallax agrees so closely with the type species B. appendiculata in all characters except 

 the forward position of the reproductive organs that it was, as I think with reason, 

 included by Michaelsen in the same genus. The main characteristic of the 

 genus is in the single dorsal diverticulum of the oesophagus whence arises the 

 dorsal vessel. This organ was figured and described by Buchholz (PI. iv, fig. 2 app.) 

 and led to his selecting the name of ' appenndiculatus ' for the species. Later it 

 was described and figured by Vejdovsky (3, PL ii, fig. 8). Both these observers noted 

 the fact that the diverticulum was composed of a bundle of parallel tubes, of which 

 Michaelsen subsequently gave a rather more detailed account in his paper upon the 

 ' Chylusgef ass-system' of the Enchytraeidae. Vejdovsky regarded the tubes as blood- 



