260 OLIGOCHAETA 



the setae of the dorsal bundles in the anterior segments are partly tridentate instead 

 of pectinate — a difference which Vaillant justly considers as at most specific. 



Three species have been referred to this genus, viz. P. barbatus, P. remifer, 

 and P. batillifer. About the first there is no question ; it is, perhaps, doubtful 

 whether P. remifer should be placed in this genus. The peculiar setae of some 

 of the anterior segments appear to difiier from those of the type-species as well 

 as from those of any other Tubificid. It is obviously desirable that we should 

 have more information about both P. reimifer and P. batillifer, before any definite 

 statement can be made as to their systematic position. 



Psammoryctes barbatus (Geube). 



Saenuris barbata, Geube, Ein Ausflug nach Triest und Quamero, 1861, p. 75. 

 S. (Naidina) umbellifera, Kesslek, Trud. Eussk. Est. St, Petersb., 1868, p. 107. 

 Tubifex umbellifer, Lankestee, Ann. and Mag. Nat. Hist., Feb., 1871, p. 93. 

 Psammoryctes umbellifer, Vejdovsky, SB. Bohm. Ges., 1875, p. 194. 

 P. barbatus, Vejdovsky, SB. Bohm. Ges., 1883, p. 224. 



Definition. Length 40 mm. ; number of segments 90. Prostomium as long as buccal segment. 

 Uncinate setae with equal prongs or with one longer than the other, the first kind found 

 from eleventh segment onwards in both dorsal and ventral bundles, the other in ventral 

 bundles of anterior segments ; no setae on XI ; palmate setae in II — X. Hab. — Europe. 



Geube's description was far too imperfect to admit of a recognition of the species; 

 hence the synonymy. The identity of Geube's species was cleared up by Vejdovsky, 

 who examined the type of 'Saenuris barbata.' This species is amply illustrated in 

 the works of Lankestee (10), Vejdovsky (13, ^4), Stolc (3) ; see also Benham (9). 



Genus Hemitubifex, Eisen. 

 Syn. Clitellio, CLAPARiiDB (in part.). 

 Tubifex, d'Udekem (in part ). 

 Peloryctes, Zengeb. 



DBPlBTiTioiir. Setae of two kinds, capilliform, and uncinate, the former only in 

 dorsal bundles. A special chamber ('vesicula seminalis') constricted ofF from 

 spermiducal gland above into which prostate opens. 



This genus comprises not only the species H. insignis, for the reception of which 

 the genus was created by Eisen in 1870, but also, as I have shown (70), the marine 

 worm 'Clitellio ater' of Claparede (3) ( = 7. benedii, d'Udekem). Possibly some 



