254 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



Order PALEONEMERTEA 



Key to the Families Represented on Pacific Coast 



1. Mouth situated immediately behind brain ; nephridia with single 

 pair of large collecting tubules and efferent ducts . . . . , 2 



2. Lateral nerves situated at base of body epithelium or external 

 to circular muscles of body walls, at least in anterior portion of 

 body; internal circular musculature relatively thin; lateral sense 

 organs present ; rhynchocoel vessels absent .... Tubulanidae 



2. Lateral nerves situated outside muscular layers in anterior por- 

 tion of esophageal region but imbedded in longitudinal muscles 

 in nephridial region and posteriorly; internal circular muscula- 

 ture enormously developed in nephridial region; lateral sense 

 organs absent ; rhynchocoel vessels present .... Carinomidae 



L Mouth situated far behind brain ; nephridia with very numerous 

 minute efferent ducts; body filiform; head sharply pointed . . 

 Cephalotrichidae 



Family Tubulanidae 



Key TO Genera 



L Lateral nerve cords at base of body epithelium or external to 

 circular musculature throughout body; cerebral sense organs 

 present Tubulanus 



1. Lateral nerve cords external to circular musculature anteriorly 

 and imbedded in longitudinal musculature in nephridial region 

 and posteriorly; cerebral sense organs absent . . . Carinomella 



Genus TUBULANUS Renier 



Seven species belonging to this genus have been found on the North 

 Pacific coast. 



Key to Species 



1. Body of somewhat homogeneous color, without definite markings 2 

 L With distinct longitudinal or transverse markings, or both . . 3 



2. Body very soft, attaining a length of nearly 2 m when fully 

 extended ; deep red, orange, or bright vermilion . . polymorphus 



2. Body minute, very slender; whitish and somewhat translucent 



i pellucidus 



3. Yellow, rosy, or greenish, with black longitudinal and transverse 

 markings. Body large, rather firm, only moderately slender, at- 

 taining a length of 50 cm or more; pale yellowish or rosy, some- 

 times with greenish tinge, with 3 longitudinal velvety black lines 

 and a series of narrow rings of similar color f renatus 



