29 



I. PROTONEMERTim. 



Two muscle layers in body wall, i.e., external 



circular and internal long-itiidinal. The lateral 



nerve cords lie outside the circular layer. 



Proboscis without stylets. Mouth behind brain. 



Fam. CarinelliDtE. 



Genus. Carinella. 



II. MESONEMEETINI. 



Two muscle layers in body wall, i.e., external 

 circular and internal longitudinal. The lateral 

 nerve cords lie in the midst of the longitudinal 

 layer. Mouth behind brain. Proboscis without 

 stjdets. 



Fam. Cephalothricid.I':. 



Grenera. Cephalothri.t 

 Carinoma. 



III. METANEMERTINI. 



Two muscle layers in bod}' wall, i.e., external 

 circular and internal longitudinal . The lateral 

 nerve cords lie beneath the longitudinal layer. 

 Mouth in front of brain. Proboscis armed with 

 stylets. 



A. Proriiynchoccelomia. 



Body long and thin. Proboscis and pro- 

 boscis sheath much shorter than body. 



Fam. EUNEMERTID^. 



Eyes j)resent. No otocysts. 

 Genus. Eunemertes. 

 Fam. OtotyphlonemertidtE. 



No eyes, but one or more pairs of 

 otocysts venti'al to brain. 



Genus. Ototypldonemertes, 



