GASTEROPODA NUDIBRANCHIATA. 



351 



From the observations of Van Ilasselt it seems that we must here arrange 



The Scarabes, Montf. 



The shell is oval, and the aperture contracted by large teeth projecting from both the columellar bide 

 as well as the outer lip : this lip is swollen, and as the 

 animal re-makes it after every half-whorl, the shell is most 

 protuberant on two opposite lines, and has a flattened 

 aspect. The animals live on aquatic plants in the Indian 

 Archipelago. 



The two genera which follow were misananged among 



the Volutes. 



Auricula, Lam., — 



Differing from all preceding aquatic Pulmonea by having 



their columella striated with large oblique channels. Their 



shell is oval or oblong ; the aperture of the shape of the Hulimus or Limnaeus ; the lip furnished with 



a varix. Several species are of considerable bulk ; but it is not ascertained if they live in marshes, 



like the Limnaeus, or merely upon their margins, after the manner of the Succinea. 



[One species, according to Lesson, lives in fresh water ; the others appear to be terrestrial, living on rocks l>y 

 the sea-side.] We find only one in France, from the coast of the Mediterranean {Auricula myosotis, Drap.) The 

 male has two tentacula, and the eyes are at their bases. [Carychium, Muller, answers so nearly to the description 

 of Auricula, that the genera ought probably to be conjoined. The typical species (C. minimum) lives under leaves 

 in shaded woods.] 



The Mblampes, Montf. (Conovulus, Lam.), 

 Like the Auricula, have prominent plaits on the columella, but their aperture has no varix, and its 

 inner lip is finely striated : the shell has somewhat the shape of a cone, of which the spire makes the 

 base. Thev inhabit the rivers of the Antilles. 



Fig;. IC2. — Auricula stambteus 



THE SECOND ORDER OF THE GASTEROPODES. 



THE NUDIBRANCHIATA.* 



They have neither a shell nor pulmonary cavity, but their branchire are exposed naked 

 upon some part of the back : they are all hermaphroditical and marine : they often swim in a 

 reversed position, the foot applied against the surface, and made concave like a boat ; and 

 they assist their progress by using the edges of the cloak and the tentacula as oars. 



The Doris, Ctiv., — 

 Have the anus in the posterior part of the back, and the brancliia; are arranged in a circle round the 



anus; and as each resembles a little arhnscule, they constitute alto- 

 gether a sort of flower. The mouth is a small proboscis, situated 

 under the anterior edge of the cloak, and is furnished with two small 

 conical tentacula. There arc other two tentacula, of a conoid figure, 

 [and lamellated structure,] which issue from the superior and ante- 

 rior part of the cloak. The organs of generation hare their on- 

 near to each other, under its right margin. The stomach is membranous. A gland, intimately inter- 

 laced with the liver, sheds a peculiar secretion, that escapes outwards by a hole mar the anna. The 

 species are numerous, and some of them of considerable size We find them on the shores of every 

 sea.f 'flu ir spawn is shed in the fnnn of a gelatinous ribbon, on rocks and sea-weeds, *\<\ 



Tin- OncMdoret, Blainv., only differ fnnn the Doris In the wider separation of their sexnal organs, whose orifices 

 communicate by a farrow drawn alone; the right side, as in the Onchidia, The Ploesnoenvt, Leuckard, hare all 

 the i of Onchidorea, and moreover the anterior edge of their cloak ia adorned with numerous branched 



tentacula. The branchial of Pttgeara, Cut., arc like those of Doris, but simpler, and furnished with two mean- 



• H dtfi if« J"i"- id lOfelber by M. da DUlnvUli Into 



what ht <**!!» a .ui,-. la,., ,n<J name Parmeepkalopkora 'nun-- 

 . libranrhlata hr tiinU. t>' u the first {tyclot" 



Dorldni Id. iV weAla/a) the 



Trltonire mid its kUlW, whirl, he dlvtdl iota 1*0 laiiulici, ar. 



a. they have two or four triitacula. 



* Tlu- S. ..(ii>l. .(..-. i. , m dtsi rtbod b, Or JokjMtOS. In the lit 

 vol. ol tin- .Irtni.'l k' .V itur.tl llutory ; ami Montagu has described 

 many British species 111 the Linnman TraHiiuttvml — r , 



