334 MOLLUSCA. 



More commonly there is one in that portion of the aperture 

 which is closed by the penultimate whorl(l). 



It is frequently observed inside of the external edge('2). 



Chondrus, Cuv. 



The aperture, as in the last mentioned Pupse, indented on the side 

 next to the spine by the preceding whorl and bordered with salient 

 laminse or teeth; but the form is more ovoid, like that of a common 

 Bulimus. 



Some of them have teeth on the margin of the aperture(3). 



Others are furnished with more deeply seated lamin?e(4). 



Here terminate that series of terrestrial Helices, the adult shells 

 of which have a tumid margin round the aperture. 



SucciNEA, Drap. 



Shell ovalj the aperture higher than it is broad, as in Bulimus, 

 but larger in proportion; margin of the aperture not tumid, and the 

 side of the columella almost concave. The shell will not receive 

 the entire animal, and it might almost be considered as a large- 

 shelled Testacella. Its inferior tentacula are very small, and it lives 

 on the plants and shrubs which line the banks of rivulets, a circum- 

 stance which has caused the genus to be considered as amphibi- 

 ous(5). 



Clausilia, Drap. 



These Mollusca formerly belonged to the genus Turbo of Linnaeus, 

 from which it has been found necessary to separate them, in order 

 to approximate them to the terrestrial Helices. The shell is long, 



(1) Turbo uva, L., Martini, IV, cllii, 1439; Turbo muscorum, L. [Pupa margi- 

 nata, Drap., 111,36, 37, 38); Pupa muscorum, Drap., Ill, 26, 27 {Vertigo cylin- 

 Jnca, Feruss. ); Pupaumhilicata, Drap. 111,39,40; P. doliolum, lb., 41,42. 



(2) Hel. vertigo, Gm., [Pupa vertigo, Drap., Ill, 34, 35); Pupa antivertigo, lb., 

 32, 33; Pupapygmeea, lb., 30, 31; Bulimus ovularis, Oliv., Voy., XVII, 12, a, b. 



(3) Bulimus zebra, 01., XVII, 10; Pupa iridens, Drap., Ill, 57; Pupa varia- 

 hilis, lb., 55, 36. 



(4) Bulimus avenaceus, Brug., [Pupa avena) Drap., Ill, 47, 48; P. secale, lb., 

 49, 50; P. frumentum, lb., 51, 52; Bulimus similis, Brug. ; P. cinerea, Drap., 

 lb., 53, 54; P . polyodon, IV, 1, 2; Helix quadride-)is, {Pupaquadr-, Drap.) lb., 3. 



(5) Succinea amphibia, Drap., IV, 22, 23 {Helix putris,!^.); S. oblonga, lb., 24. 

 The genera CocHLOHTDUA, Feruss., Uucina, Oken, Tassade, Huder, correspond 

 to the Succineae. M. Delamark at first styled them Amphibulimi. The Amphib- 

 ulime encapuchonne , Lam., Ann. du Mas. VI, Iv, 1, may also form a Testacella. 



