MOLLUSCA. 787 



Aplysia auctor. Body elongate, not truncated posteriorly, angus- 

 tate. Dorsal operculum of branchiae including a membranous horny 

 shell. 



Comp. BOHADSCH De quibusd. animalib. marinis, pp. i 53, Tab. I. iv. 

 CUVIEB Ann. du Mus. n. pp. 287 314, PI. n. Mottusq., Mem. ix.; DELLE 

 CHIAJE Memorie, I. pp. 25 76, Tab. n. v. 



These animals, on a first impression, resemble gigantic slugs (Limaces). 

 The ear-shaped tentacles have given occasion to stamp this genus with the 

 name of Sea-hare (Lepus marinus). They live on fuel; and shed a purple 

 fluid at the margin of the mantle. 



Sp. Aplysia depilans L., BOHADSCH 1. 1. Tab. i. iv. RANG 1. 1. PI. 16, 

 CUVIEB R. Ani., ed. ill., Moll. PI. 33; one of the largest species; of this 

 Mediterranean species, under the name of Lerncea, BOHADSCH gave 1. cit. 

 a detailed description and a masterly anatomical investigation. In that 

 and in other seas still different species of this genus are found. The eggs 

 are laid in long tortuous strings. The development of Aplysia has been 

 observed by VAN BENEDEN, Ann. des Sc. nat. 2e Serie, xv. pp. 123 128, 

 PI. i. 



Notarchus Cuv. 

 Bursatella BLAINV. 



Note. RANG 1. 1. concludes that these genera form sections only of the 

 great genus Aplysia. Of Notarchus the same has been noted by the cele- 

 brated voyagers QUOY and GAIMAKD, Voyage de V Astrolabe, Zoologie, n. 

 p. 312. 



Gastropteron MECK. Tentacles none. Margins of foot ex- 

 panded into ample wings. Shell none. Branchiae pectinate, 

 almost entirely naked; a small duplicature of mantle, produced 

 beyond the body into a filiform lacinia. 



Sp. Gastropteron Meckelii J. F. J. KOSSE, Diss. de Pteropodum ordine at 

 novo ipsius genere, Halae, 1813, 4-to, figs, u 18, Clio A mati DELLE CHIAJE, 

 Memorie, pp. 5359, Tab. n. figs, i 8; CANTBAINE 1. 1. PI. 4, fig. 4; a 

 small mollusc from the Medit. Sea, of a rose-red colour ; the only species 

 hitherto known. 



Acer a MUELLER (in part), LAM. (Doridium MECK., Lobaria 

 BLAINV.). Tentacles none. Veil of head large, separated from 

 mantle by a transverse furrow. Vent, orifice of generation, bran- 

 chiae and heart placed at the right side; branchiae posterior. A 

 small shell included in the posterior part of mantle, flat, calcareous 

 at the incurved apex, elsewhere membranous, thin. 



Comp. on this and the two following genera CUVIER Ann. du Mvs. xvi. 

 pp. i 18, Mollusq., Mem. x. 



502 



