586 GASTROPODA. [Opisthobranchia; 



Remarks. This species appears to have the characters of a typical 

 Antiopella, except that the jaws are not distinctly and strongly denti- 

 culate. It differs from the British A. cristata in its colour and in the 

 size of the rhinophores and crest, perhaps also in the jaws. (Eliot.) 



Fam. FIONIDJE, Alder and Hancock. 



Body elongated ; rhinophores simple, not retractile, without 

 pockets ; cerata devoid of cnidosacs, arranged as in Eolididce ; anus 

 latero-dorsal. Jaws horny. Radula uniserial ; teeth arched, with 

 pectinated edge and with a median cusp which is longer than the 

 side cusps. 



Genus 1. FIONA, Hancock and Embleton, 1853. 



Fiona, H. & E., A.M.N.H., xv, 1853, 10. Type: F. nobilis, H. & E. 

 Oithona, Hancock and Ernbleton, 1851. Hymenceolis, Costa, 1866. 



Body oblong-elliptical ; rhinophores simple, resembling the oral 

 tentacles. Cerata elongated, with a membranous fringe on the inner 

 sides. Genital orifices separate. Jaws corneous, with a denticulate 

 cutting-edge. 



Distribution. Atlantic, Indian Ocean, Pacific. 



These animals are pelagic, and are usually found on Fucus. Ac- 

 cording to Dr. Ball, their nouriture consists of Veletta. 



1. Fiona marina, Forskal, 1775. Plate 23, fig. 21. 



Limax marina, Forsk., Descript. Animal, &c., 1775, 99. Fiona marina, 

 Bergh., Opistobr. Camp. " HirondeUe," 1892, 6, pi. 1 f. 7-16 (anatomy) ; 

 Zool. Jahrb. Syst., xiii, 1900, 239 ; Basedow and Hedley, T.R.S. 

 S.Aust., xxix, 136; Bergh, Ckall. Rep., x, 9. F. nobilis, Aid. & Hanc., 

 A.M.N.H., xv, 1853, 10. F. atlantica, Bergh., Vidensk. Meddel. f. 

 naturhist. Foren, 1857, 273. F. marina, var. pacifica, Bergh., Nudibr. 

 Gastr. Moll., 1879, 86. F. pinnata, Eschscholtz : Bergh., Kenntn. 

 /Eolidaden, 1874, 606. Hymenceolis elegantissima, Costa, Ann. Mus. 

 Zool. Napoli, 1866, 64, 80. &olis plicata, Button, T.N.Z.L, xiv, 1881 

 (1882), 166, pi. 6, f. 1. 



Head, neck, and body white. Branchice in close transverse rows 

 on the back, dark brown, each margined with white. Body not tapering 

 behind. Margin of foot fringed and crumpled, except near the head, 

 where it is simple ; it is divided in front, but not produced. On the 

 side, below the cerata, several rows of small white papilla? (?) arranged 

 in festoons. Rhinophores distant, subulate, tapering, projecting out- 

 ward, white. No eyes. Oral tentacles shorter, thickened at the base, 

 tapering, projecting laterally, and curved backward ; white. (Hutton.) 



Length, about 20 mm. 



Dentition 0+1 + 0. About 17 or 18 teeth on the radula, in a 

 single series. Each tooth crescent-shaped, with a pointed tooth in 

 the centre, and 6 denticles on each side. Jaws 2. the apices acute and 

 denticulated, the posterior portion flattened (Hutton, T.N.Z.L, xiv, 

 166, pi. 6, f. F, a, b). 



