668 GERARDA STIASNY-WIJNHOFF 



like branching ; as a rule with metamerically arranged loops 

 between the three longitudinal vessels. 

 Sub-ordo I. Polystilifera (Brinkmann). 



Hoplonemertini with many stylets on a crescent-shaped 



^^ " base. Proboscis pore and mouth are separate or open 



l-T' \ separately in a common atrium. The muscle-coats of the 



rhynchocoelomic cavity interlace and become complicated 



as a rule. 



Sub-ordo II. Monostilifera (Brinkmann). 



Hoplonemertini with one stylet on a handle-shaped base. 

 The mouth opens into the rhynchodaeum. The rhyncho- 

 I coelomic wall never shows interlacing, and consists of an 



inner longitudinal and an outer circular muscle-coat. 

 The sub-ordo Polystilifera contains the following groups : 

 Tribus I. Pelagica (Brinkmann). 

 ' Pelagic Polystilifera without a distinct snout. Cerebral 



organs, nephridia, rhynchocoelomic diverticula, meta- 

 meric blood-vessels, and oesophagus absent. Testes only 

 in stomodaeal region. Gonopores ventral. 

 Tribus II. Eeptantia (Brinkmann). 



Polystilifera with cerebral organs, rhynchocoelomic 

 diverticula, nephridia, and oesophagus, and with meta- 

 merically situated gonads in the intestinal region. 

 Sub-tribus I. Archireptantia. 



Without a snout. Central rh^aichocoelomic diverticula. 

 Small dorsal ganglia and a primitive cerebral organ. 

 Different parts of stomodaeum sharply separated and well 

 developed. Nephridia with a large, distal efferent duct. 

 Without metamerical Aascular loops. 

 Sub-tribus II. Eureptantia. 



With a snout. Peripheral rhynchocoelomic diverticula. 

 Cerebral organs with a sac. Large, free dorsal ganglia. 

 Different parts of stomodaeum continued into each other. 

 Nephridia with, as a rule, proximal efferent ducts. With 

 metamerical vascular loops. 

 Leyden, 



iMarch 1. 1923. 



