ELYSIID.E. 31 



angulated, with a central black stripe, the sides of which, as 

 well as the tentacles and the area round the eyes, are yellow or 

 fawncoloured : tentacles of moderate length, linear and cylin- 

 drical ; on each side of the back near the vent is a slight ridge 

 with three or four pale tubercular spots. L. O2. 



HABITAT : In rock-pools between tide-marks, on Chorda 

 tomentaria and Dumontia filiformis, Ealmouth (Cocks) . [Burg- 

 head, Moray Firth (Gordon).] 



Family II. ELYSHDJE, (Elysiada) Alder and 

 Hancock. 



Without cloak or gills: sides of the body produced into 

 foliaceous lobes: tentacles 2 or 4, generally folded longitu- 

 dinally: vent dorsal or latero-dorsal : odontophore denticulated ; 

 no jaws. 



Though the mollusks of this family have no specialized gills, 

 the expanded lobes of the body, on the internal surface of which 

 the blood-vessels are ramified, make a nearer approach to spe- 

 cialization than in other members of the group. Several 

 handsome species of the family are found in the seas of warm 

 climates ; with us it is represented by a single species only. 



Genus ELY'SIA*, Bisso. 



[PL I. f. 6.] 



BODY limaciform, with the sides expanded into lobes folding 

 over the back : tentacles 2, longitudinally folded : gastro- 

 hepatic system much branched : vent latero-dorsal, in front of 

 the heart : odontophore having a single row of spines. 



This genus is the Actceon of Oken but not of De Montfort-; 

 Aplyslopterus of Delle Chiaje is also a synonym. 



ELYSIA VI'RIDIS, Montagu. 



Laplysia viridis, Mont, in Linn. Trans, vii. p. 76, pi. 7. f. 1. E. viridis, 

 F. & H. iii. p. 614, pi. CCC. f. 3. 



BODY ovate-oblong, depressed, grass-green, with bright 

 * [Possibly from e\vw, to fold inwards.] 



