128 THE ANNELIDA POLYCHAETA. 



Ke%j to Genera. 



a. Notocirrus as long as the setigerous lobe. 



h. Foliacecus ventral and dorsal cirri present on the first free somite; palpi as long as the first 



tentacular cirri, visible from above Paraiospilus Viguier. 



66. No such foliacecus cirri on first free somite; palpi small, not visible from above. 



lospilus Viguier. 

 aa. Notccirri shorter than tTie setigerous lobe Phalacrophnrus GreefT. 



Lacydoniidae. 



The third family, the Lacydoniidae, embraces only Lacydonia, which differs 

 from the phyllodocids proper as well as from the other phyllodocoids in having 

 four, well-developed, true jaws like those of the Aphroditidae. There are four 

 tentacles but no palpi, and only a single pair of tentacular cirri. Non-pelagic. 



Otopsidae. 



Of more doubtful relationship is the family Otopsidae recently estabUshed 

 by Ditlevsen for the new genus Otopsis, a form with three tentacles, no palpi, 

 no armature to the proboscis, and no eyes. Setae all simple (Danish Ingolf 

 exped., 1917, 4, pt. 4, p. 67). 



PiSIONIDAE. 



This family is not represented in the collections made by the Albatross. 

 It was created by Levinsen (1866) for the genus Pisione, which Grube had applied 

 (1857) to his species P. oerstedi occurring near Valparaiso, and which he had 

 placed in the Phyllodocidae, regarding it as a form transitional between that 

 family and the Glyceridae. Ehlers points out its resemblances in different 

 characters to the Aphroditidae, Nepthydidae, Hesionidae, Syllidae, and Gly- 

 ceridae. He added a second species, P. contractu, from the South American shore 

 near Callao (Festschr. K. gesellsch. Gottingen, 1901, p. 60). A second genus, 

 Prageria, is added by Southern (Proc. Royal Irish acad., 1914, 31, pt. 47, p. 61). 



Key to Genera. 



a. Genital papillae greatly elongate; notocirrus of second parapodia filiform, elongate like a ten- 

 tacular cii-rus Pisione Grube. 



aa. Genital papillae absent; notocirrus of second parapodia small, globular, as in the succeeding ones 



Pratjeria Southern- 



