NO. 13 COE : REVISION OF THE NEIMERTEAN FAUNA 259 



Ocelli. A single pair present in larval stages only. 



Color. Whitish, gray, or pale yellow, often with pinkish or greenish 

 tinge. 



Nephridia. The numerous metanephridia of this species have been 

 described by Coe ( 1930) . 



Habitat. Very common under stones between tides and below in 

 muddy places; often associated with decaying organic matter. 



Distribution. North Atlantic coast of America, Alaska, British Co- 

 lumbia, Puget Sound to southern California. 



Regeneration. Posterior regeneration of body fragments takes place 

 rapidly but anterior regeneration has been observed only when cut in 

 front of brain. In the latter case the original proboscis is discharged and 

 a new one replaced from the new cephalic tissues after a month or more. 

 Fragments of the body may remain alive for several months, but a new 

 brain has not been restored in any of the cases under observation. 



Reproduction. Eggs from ripe females may be obtained during the 

 warmer months of the j^ear. These are usually deposited at night in a 

 string of mucus and are often fertilized at time of deposition or before 

 if both sexes are associated. 



Development of the direct type occurs also when the eggs are cut 

 from the body of the worm and fertilized artificially. The larva may be 

 fed with cultures of diatoms associated with other minute organisms. As 

 in the case of the other species which have been studied, development 

 proceeds slowly; the larva has a single pair of ocelli, as described for the 

 preceding species. 



Order HETERONEMERTEA 



Key to Families 



1. Head usually broad and rounded, capable of being withdrawn 

 into body when strongly contracted ; with shallow oblique ce- 

 phalic grooves but without lateral longitudinal grooves. Cutis 

 glands voluminous; connective tissue layer very thick. Proboscis 

 sheath short; proboscis musculature of two layers of which the 

 outer is circular; without muscular crosses. Cephalic glands 

 voluminous Baseodiscidae 



1. Head variable in shape; pointed or rounded, according to state 

 of contraction; with deep lateral longitudinal grooves (except 

 in ZygeupoHa). Proboscis musculature usually of three layers 

 (circular, longitudinal, circular) with muscular crosses. Cephalic 

 glands relatively few Lineidae 



