NO. 4 HARTMAN : SPIONIDAE FROM CALIFORNIA 305 



eyes in a nearly transverse line and says, "De koplob is zwak ingesneden 

 en voorzien van twee paar oogen, die alle op een dwarse lijn staan." In 

 ours the 4 eyes are in quadrangular arrangement. The nature of uncini 

 and the kind of pygidium were not disclosed by Horst. 



Genus POLYDORA Bosc 



Polydora is distinguished from Boccardia in lacking branchiae on 

 segments anterior to the modified fifth segment. It was originally erected 

 for P. cornuta Bosc, from South Carolina, but was not sufficiently de- 

 fined to reidentify; the type of the genus remains unknown except as a 

 member of this group. The genus has been revised by Mesnil (1896), 

 Soderstrom (1920), and others. 



Key to Species of Polydora from California 



1. Prostomium and palpi very short; major spines of fifth modified 

 segment falcate with a long, lateral sheath ; pygidium with about 

 14 papillae ; commensal with hermit crab P. commensalis, p. 308 



1. Prostomium with palpi otherwise; major spines of fifth segment 

 without a long sheath if falcate; pygidium without numerous 

 papillae; not commensal with hermit crab 2 



2. Pygidium with 4 cirri disposed in a cross; major spines of fifth 

 segment of 2 kinds, both with bristly top (pi. 45, figs. 12, 13) ; 

 prostomial ridge very narrow, greatly eclipsed by the large peri- 

 stomium ; bright yellow in life .... P. citrona, ^. ?>\0 



2. Pygidium disklike ; major spines of fifth segment otherwise ; pro- 

 stomial ridge not so reduced 3 



3. With conspicuous bundles of heavy spines in a few posterior seg- 

 ments; major spines of fifth segment falcate, with a large over- 

 hanging flange (pi. 48, fig. 39) ; in coralline hummocks . 

 P. armata, p. 306 



3. Without such spinous fascicles in posterior segments; major 

 spines of fifth segment without overhanging flange .... 4 



4. Prostomial caruncle with a median antenna; major spines of 

 fifth segment falcate with sharp accessory tooth in concavity 

 (pL48, fig. 48) P. //>m, p. 309 



4. Prostomial caruncle without median antenna; major spines of 

 fifth segment otherwise 5 



