SIGALIONIDAE. 89 



number and different form and proportions of its papillae, and especially in the 

 detailed structure of the setae of the different series. 



SiGALIONIDAE. 



The body is most commonly long and narrow, cyhndrical and vermiform, 

 or, more rarely, short and somewhat flattened as is particularly the case in Eulepi- 

 dinae. 



The prostomium is rounded. The eyes may be four, two or none. When 

 present all are sessile. The tentacles in number are three, two or only one. 

 The palpi, always present, are long and attenuated distad, smooth throughout. 

 The lateral tentacles in most genera are fused, excepting at their tips, with the 

 first parapodia which are carried well forward. 



Parapodia bii-amous. Notopodia bearing simple setae. The neuropodia 

 may also bear only simple setae (EulepicUnae) , but more commonly (Sigalioninae) 

 bear composite setae either exclusively or mixed with simple setae. 



Elytra borne on somites II, IV, V, VII and on the alternate succeeding 

 somites caudad to the twenty third or, less commonly, to the twenty seventh, 

 after which both cirri (cirriform branchiae) and elytra occur on all somites aUke. 



The proboscis ends in a marginal crown of papillae and is armed with four 

 horny jaws. 



The members of this family occur from the httoral region down to depths 

 of several hundred fathoms. They often occur buried in mud or sand some 

 centimeters below the surface. 



Key to Genera. 



a. All setae simple; body short and somewhat flattened Eulepethinae, nom. nov. 



b. Elytra on somites II, IV, V, VII etc Eulepethus, nom. nov. 



66. Elytra on somites II, III, IV, VI, VII etc Pareulepis Darboux. 



aa. The setae in part composite; body usually long and slender, cylindrical, less commonly short. 



Sigalioninae. 

 b. With no median tentacle; lateral tentacles small, attached at anterior end of proboscis; branchiae 



well developed Sigalion Cuvier. 



66. A median tentacle present; branchiae well developed or not. 

 c. Tentacle one, the laterals absent. 



d. Dorsal cirri or branchiae none; no setae on the first somite Pholoe Johnston. 



dd. Branchiae present but rudimentary; setae on the first somite Eupholoe Mcintosh. 



cc. Tentacles three; branchiae well developed. 



d. Lateral tentacles free only at tips, fused proximally with parapodia of the first somite. 

 e. Median tentacle long bearing on its ceratophore a pair of prominent spatulate ctenidia; 

 elytra completely covering the dorsum. 

 /. Composite setae falcigerous, distally sometimes flagelliform. 



