632 GERARDA STIASNY-WIJNHOFF 



conclusion I share. All these facts show evidently that 

 Biirger's system of Metanemertini does not give the real 

 relationship of the genera. Brinkmann gives another 

 system, that seems to suit much better our present state of 

 knowledge. The armature of the proboscis is the distinctive 

 character. In most armed Nemerteans the proboscis has one 

 stylet on the top of a somewhat pear-shaped handle (Text- 

 fig. 4). The only known exception to this rule was till fifteen 

 years ago Drepanophorus ; then the Valdivia material showed 

 that some of the pelagic Nemerteans have a crescent-shaped 

 handlelike Drepanophorus with many small stylets (Text-fig. 5) 



Text-fig. 4. 



sac. 



bos 

 Armature of the proboscis of Stichostemma eilhardi after 

 Montgomery, 1894 ('Zool. Anzeiger ', Jahrgang 17, fig. 3) 

 (Monostilifera). 



and Brinkmann (4) confirmed this discovery of Burger 

 for all pelagic forms. He divides the Hoplonemertini into 

 two sub-orders, Polystilifera and Monostilifera (4, p. 145). 

 The Monostilifera contain all genera of Metanemertini (Burger), 

 with the exception of (1) Malacobdella (=Bdellomorpha, 

 Verrill), (2) the pelagic genera, and (3) Drepanophoridae. 

 The Polystilifera consist of all pelagic Nemerteans and the 

 genera Drepanophorus (Hubrecht), and Uniporus (Brinkmann). 

 There can be no doubt as to the naturalness of these sub-orders. 

 Both contain a great number of genera and species, which 

 are widely different in structure, but still are more closely 

 related to each other than to any other form. This is shown 

 by the position of the mouth, which in the Anopla lies behind 



