EOLis. 589 



OITHONA, Alder and Hancock. 



" Body elongated, liniaciform ; head with four h'near 

 tentacles, without sheaths, constituting two pairs, both 

 subdorsal ; the anterior pair corresponding to the oral 

 tentacles of Eolis, being situated considerably behind the 

 lips. Mouth with corneous jaws. Branchiae papillary, 

 clothing irregularly a sub-pallial expansion on the sides 

 of the back, and meeting posteriorly ; a produced mem- 

 branous margin or fringe runs down the inner side of each 

 papilla. Vent latero-dorsal, situated towards the right 

 side. Orifices of reproductive system separate ; situated 

 below the tentacles on the right side." 



O. NOBiLis, Alder and Hancock, MSS. 



Body pale bntf, or whitish, smooth. Tentacula long, 

 tapering, equal. Branchiae linear, conical, with strongly- 

 waved and wide lateral fringes, their apices (also the 

 back) iridescent. Foot long and lanceolate. Length 

 two inches. 



Discovered by Mr. Cocks, under a stone at low- 

 water, near Bar Point, Falmouth. Described by the 

 authors of the " British Nudibranchiata," in a communi- 

 cation to the British Association at Ipswich in 1851. 



EOLIS, CuviER. 



Body ovate or linear ; no mantle. Head with four 

 non-retractile tentacles, not invested by sheaths ; almost 

 always linear ; the dorsal ones rarely bulbed, sometimes 

 ringed. Branchiae simple, cylindrical, papillose, ranged 



