OF PLYMOUTH AND THE ENGLISH CHANNEL. 233 



Family SIGALIONIDiE. 



Prostomium rounded, often with a nuchal collar posteriorly. 

 No facial tubercle. Median tentacle, when present, generally long, 

 produced from the median part of the prostomium and with ctenidia 

 at the sides of the base (ceratophore). 

 Lateral tentacles fused with the base of the tentacular cirri, the tips 



only emerging. 

 Eyes four, occasionally only two, or absent. 



Palpi long, attenuate, and smooth, with buccal ctenidia at the bases. 

 Body long and narrow. 

 Pharynx, with f , {j, yf papilUe and teeth. 

 First pair of feet carried in front of the head, 

 Notopodial chsetse spinous and tapering. 

 Neuropodial chsetse compound, the terminal region being often long, 



multiarticulate, and bifid. 

 Ctenidia on all the feet. 



Elytra and cirriform gills alternate in the anterior segments up to the 

 twenty-sixth ; those of the middle and posterior part furnished with 

 both elytra and cirriform gills. 

 Sthenelais, Kinberg. 



Elytra partly fringed with a variable number of minute papillse, 

 entirely covering the dorsum. 

 EuSTHENELAis, McIntosh. 



Elytra unknown. Known only from a fragment. 

 SiGALiON, Aud. et Edw. 



Elytra partly fringed with pinnate processes, or with long papillae 

 arising from an axis ; entirely covering the dorsum. 

 Leaniea, Kinlerg. 



Elytra not covering the dorsum anteriorly, smooth in outline and 



surface. 

 A median and two lateral tentacles. 

 Pholoe, Johnston. 



Elytra partly fringed with long cilia with moniliform tips. Median 



portion of dorsum exposed. 

 A median tentacle only. Two pair of eyes. 



Genus STHENELAIS. 



Prostomium rounded anteriorly, with a nuchal collar posteriorly 



in the preparations. 

 A pair of ctenidia at the base (ceratophore) of the median tentacles. 

 Lateral tentacles fused with the first foot; tentacular cirri more 



or less separate. 



R 2 



