POLYCERIDiE. 319 



I'etractile ; branchiae pinnate and non-retractile, placed round 

 the anus almost on the centre of the back. Mouth without oral 

 tentacles or veil, andwithoutcoUar or jaws; odontophore broad, 

 bearing simple spines. 



Nembrotha, Bergh. 



Didr. — 6 sp. Pacific. N. nigei'iHma^ Bergh. 



Body limaciform, back and sides not separated ; tentacles 

 short, lobiform ; branchise not retractile, sparsely foliate, almost 

 in the middle of the back; foot narrow; labial armature small 

 or none (?). 



§ B. Rhinophores non-retractile ; odontophore narrow. {Sten- 

 oglossae.) 



GrONiODORis, Forbes, 1840. 



Si/n.— Doriprismatica, d'Orb., 1837 (part). Pelagella, Gray, 

 1850. 



Disfr. — 9 sp. Universal. G. nodosa, Mont, (xc, 10). 



Body rather depressed ; mantle distinct with waved or scal- 

 loped margin. Rhinophores laminated ; oral tentacles flattened ; 

 branchiae non-retractile ; odontophore with four plates in each 

 transverse row ; the two next the median line bearing each a 

 large spine ; no central plate. A spinous buccal collar. 



Aethedoris, Abraham, 1876. 



Distr. — A. Indica, Aid. and Hanc. Madras Coast. 



Alder and Hancock figure in vol. 5 of the Zoological Society's 

 Transactions, a form belonging to a new genus " apparently 

 related to Goniodoris." As no specimen came into their hands, 

 they could give no description. The most striking character- 

 istic seen in the drawing is the expansion of the bilobed head, 

 each lobe being semicrescentic, with the apex curved backwards 

 and the margin bearing twelve to fourteen conical dentations. 



Idalia, Leuckart, 1828. 



Syn. — Euplocamus, Philippi, 1836 (part). 



Distr. — 8 sp. Europe and China. I. aspersa, Aid. and Hanc. 

 (xc, 11). 



Body convex, smooth. Mantle indistinct, the margins bearing 

 filaments, generall}^ longest in front. The head is produced 

 anteiiorly. Rhinophores linear, laminated. Branchiae simply 

 pinnate, non-retractile. Odontophore with four spines in each 

 transverse row, the two middle ones large, no central spines. A 

 spinous buccal collar. 



IDALIELLA, Bergh, 1881. Differs in the absence of cirri in 

 the middle of the back, and in the lateral lamellae of the booklets 

 on the lips. I. insequalis, Forbes and Hanley. 



