COE: NEMERTEANS OF WEST AND NORTHWEST COASTS. 105 



or very pale salmon posteriorly, much obscured by deep gi-eeii 



color of intestinal tract ... P. californica, p. 226. 



4. Six pouches of accessory stylets ; 11 to 13 proboscidial nerves ; 



whitish, pinkish or flesh-color ... P. carnea, p. 225. 



AA. Proboscis sheath extends nearly or quite to posterior end of body ; 



l)ody usually not very slender . . . . . . E. 



E. Proboscis provided with stylets, intestine not dendrocoelous . F. 



F. Proboscis sheath without caecal appendages ; proboscis armed 

 with single central stylet, besides 2 or more pouches of acces- 

 sory stylets ......... G. 



G. Ocelli numerous, extending posteriorly along lateral nerve 

 cords beyond the bi'ain ; basis of central stylet massive, 

 with flattened or concave posterior end. 



Zygonemertes, p. 212. 



1. Color usually rather pale green, occasionally flesh colored, 



pale yellow, or white, especially anteriorly ; central stylet 

 short, about half as long as basis, not remarkably stubby ; 

 usually 2 or 3 accessory stylets in each of 2 lateral pouches ; 

 10 or 11 proboscidial nerves . . Z. virescens, p. 21i. 



2. Color usually rather dark olive green ; central stylet remark- 



ably stubby, often less than half as long as basis which is 

 much serrated on posterior border ; commonly o accessory 

 stylets in each of 2 lateral pouches ; 12 proboscidial nerves. 



Z. thalassina, p. 213. 

 8. Body small, whitish, with a tinge of yellow ; central stylet 

 rather slender ; ocelli extend along lateral nerves for 

 about two-fifths the length of esophageal region. 



Z. alhida, p. 216. 

 GG. Ocelli do not extend posteriorly beyond brain ; basis of cen- 

 tral stylet commonly (but not always) rounded posteriorly. 



H. 

 H. Body usually not very small ; ocelli usually numerous, 

 always more than 4 in Pacific coast species. 



Amphiporus,! p. 233. 



a. Body very gelatinous, with an enormous development of 



the body parenchyma. 



1. Body shoi-t and broad ; ocelli large, 30 or more on each 



side of the head ; cerebral sense organs extremely 



small, situated in front of brain. 



A. gelatinosus, p. 259. 



' Two species, A. brunneus and A. drepanophoroides (p. 282), which cannot 

 be referred to any in this key were described by Griffin ('98) from Puget Sound. 



