380 POLYCERID^. 



Ancula, Loven, 1846. 



Syn.' — Miranda, Aid. and Hanc, 1841. Drepania, Lafont, 

 1874. 



Distr.- — 3 sp. N. Atlantic 0. A. cristata, Aid. and Hanc. 

 (xc, 12). 



Body limaciform, smooth. Mantle obsolete, forming an indis- 

 tinct ridge near the branchiae, bearing one or more appendages. 

 Rhinophores laminate, bearing styliform basal appendages. 

 Head produced at the sides into tentacular processes. Odonto- 

 phore with four spines in each transverse row, the two next the 

 median line large and broad, with the inner margin denticulated ; 

 no central spine. A spinous buccal collar. 



M. Lafont states his Drepania to differ from Ancula in the 

 head bearing two elongated tentacles analogous to those of 

 Eolis, in the branchias not being surrounded by linear appen- 

 dages, and in the rhinophore carr^ang but one filament instead 

 of two. Unless the lingual character proves to be importantly 

 different from that of Ancula, it would seem advisable to unite 

 Drepania with the latter genus. 



POLYCERA, CuV., 1811. 



Syn. — Themisto, Ol^en, 1815 (part '. Cufgea, Leach, 1820. 



Distr. — 11 sp. Europe, Cape of Good Hope, Australasia. P. 

 quadrilineata^ Miill. (xc, 18\ 



Body limaciform. Mantle indistinct, forming a supracapital 

 veil, and a tuberculated ridge on the sides. Rhinophores lami- 

 nated. Branchise non-retractile, with lateral appendages. Odon- 

 tophore with twelve to sixteen plates in each transverse row, 

 the two near the centre large and bicuspid ; no central spine. 

 Lateral corneous jaws. 



PALio, Gray. Frontal veil short, bilobed, tuberculated on the 

 edge ; gills branched, with more than one tubercular appendage 

 on each side. P. ocellata. 



POLYCERELLA, Verrill, 1880. Body elongated-ovate, having the 

 the same form as Polycera. Mantle little developed. Dorsal 

 tentacles (rhinophores) not laminated and not retractile, without 

 sheaths. A row of papillae along each side of the back, extending 

 beyond the gills. Gills three, pinnate, situated in the middle of 

 the back, nearl}^ as in Polycera. Foot auricled. Odontophore 

 with six rows of teeth ; median row absent ; inner laterals large, 

 curved, with three denticles, two outer rows much smaller, 

 simple, hook-shaped. P. JSmertoni, Yerrill. New England. 



Brachychlanis, Ehrenb., 1831. 



Distr. — B. pantherina, Ehrenb. Bed Sea. 



Mantle very small, forming a dorsal area, with narrow, 

 upturned border. Rhinophores laminated, arising in front of 

 the mantle-margin. Branchiae retractile. Mouth terminal. 



