NO. 13 COE : REVISION OF THE NEMERTEAN FAUNA 277 



47. Cerebratulus signatus Coe, 1905 



C. signatus Coe, 1905a. 



Habitat. Dredged from sandy, shelly bottom at a depth of about 

 110 m. 



Distribution. Known only from a single specimen dredged in the 

 Bering Sea. 



Genus DIPLOPLEURA Stimpson 



48. Diplopleura vivesi (Joubin), 1905 



Langiavivesi ]o\ihm,\905. 



Habitat. In fine sand at low-water mark. 



Distribution. At present known from only a single specimen collected 

 at La Paz, Lower California, Mexico. 



Order HOPLONEMERTEA 



Key to Suborders 



1. Armature of proboscis consists of central stylet with truncated 

 conical or pear-shaped basis and usually 2 or more pouches of 

 accessory stylets; mouth and proboscis opening usually united 

 Monostylifera 



1. Armature of proboscis consists of sickle-shaped basis bearing 

 numerous small stylets and usually several pouches of accessory 

 stylets; mouth and proboscis opening separate or united in 

 short atrium Polystylifera 



Suborder MONOSTYLIFERA 



Key to Families 



1. Statocysts absent; ocelli usually present 2 



1. Statocysts present; ocelli absent .... Ototyphlonemertidae 



2. Body long and slender; cerebral sense organs small, situated 



in front of brain 3 



2. Body usually relatively short and broad ; cerebral sense organs 

 large, situated beside, behind, or in front of brain 4 



3. Proboscis sheath not more than ^ as long as body; proboscis 

 short ; ocelli usually numerous, occasionally only one or 2 pairs 



or none Emplectonematidae 



