(i CLASS XIII. 
colour is purplish or blue and the length nearly 1} inches. See Proceed. 
Zool. Soc. 1836, pp. 113—189. These animals are found in the Atlantic 
Ocean principally between the tropics. 
Scyllea L. Body compressed, with foot furrowed longitudi- 
nally. Head furnished with two tentacles. Back with two expan- 
sions or membranous and flexible wings on each side. Branchiz 
penicillate, composed of filaments, scattered over back, especially 
crowded in the wings. 
Sp. Scyllea pelagica L., Cuv. Ann. du Mus. vi. pp. 416, 417, Pl. 61, figs. 
1—7, Mollusg., Mém. vi.; Buatnv. Malac. Pl. 46, fig. 5; this species 
attaches itself by its furrowed foot to Fucus natans, and is found in the 
Atlantic ocean ; Scyll. ghomfodensis observed by FoRSKAL in the Red Sea 
appears to be the same species. Deser. Animal. p. 103, fig., Tab. 39, 
figs. C.c. Anatomy, ALD. and Hano. Monogr. Fam. 2, Pl. 5. 
Doté OKEN’, Melibea (or Melibea) Rana. Body limaciform, 
with foot narrowed posteriorly. Mouth with a circular velum. 
Two filiform tentacles, defended by an ample cup-shaped sheath. 
Branchiz papillose, grouped in muricate clavee, disposed in a double 
lateral row on the back. Apertures of generation and of rectum 
at the right side. 
Sp. Doto coronata, Doris coronata GMEL. (species of T’ritonia Cuv.), BoMME 
Verh. van het Zeewwsch Genootsch. 1. 1769, Tab. Ul. bl. 314, cotfed or 
crowned Sea-slug JOHNSTON, Ann. of Nat. Hist. 1. p. 117, Pl. 3, figs. 
5—8, D’Orzpiany, GuéRIN Magasin de Zool. 1837, Mollusg. Pl. 103, 
Anatomy in ALD. and Hance. Monogr. Fam. 3, Pl. 4. 
Tritonia Cuv. Body subtetragonal or compressed, elongate, 
anteriorly rotundate, posteriorly acuminate. Apertures of genera- 
tion and of rectum at the right side, with vent situated behind the 
genital orifice. Two tentacles retractile into a sheath. Circular 
velum in front of mouth. T'wo lateral maxille, acute, with margin 
denticulate. Branchiz arborescent at the sides of back. 
a) With arborescent branchiee remote, and sheath of tentacles with margin 
laciniate. ; 
Dendronotus ALD. and Hanc. 
Sp. Tritonia arborescens Cuv., Doris arborescens GM., Cuv. Mollusg., Mém. 6, 
figs. 8—10 (probably not specifically different from Doris cervina GMEL., 
the antlered Sea-slug Bomme, 1. 1. 111. bl. 290, fig. 1). Compare, on the 
1 Lehrb. der Zoologie, 1. 1815, s. 273. 
