364 MOLLUSCA. 



bottom of the aperture, which seems to indicate a relation with the 

 Terebrse of Brugieres(l). In the 



PiRENA, Lam., 



We not only find this little sinus below, but likewise a second on 

 the opposite side(2). 



These two subgenera, as well as the Melaniae, inhabit the rivers 

 of southern Europe and of all hot countries. 



There are two genera, detached from the Volutae, which, but 

 that they are operculated and have but two teutacula, would 

 resemble the Auriculae, that we think may come here, viz. 



Action, Montf.(3) — Tornatella, Lam., 



Where the shell is elliptical, the spire but slightly salient, the aper- 

 ture lengthened into a crescent and widened below, and the base of 

 the columella marked by one or two large plicae or oblique callosi- 

 ties(4); and the 



Pyramidella, Lam. 



Where the spire is turreted, the aperture crescent-like and wide, and 

 the base of the columella obliquely contorted and marked with sharp 

 spiral plicae(5). 



Janthina, Lam. (6) 



The form of the animal separates the Janthinac from all the prece- 

 ding genera. Their shell, however, is similar to that of the terres- 

 trial Limaces, the columellar margin being also indented, but 

 slightly angular at the external edge, and the columella somewhat 

 extended beyond the half-oval, which, without this prolongation, 

 would be formed by that edge. 



(1) Melan. buccino'idea, Feruss., Mem. de la Soc. d'Hist. Nat. de Paris, tome I, 

 pi. vii, f. 1—11, &c. See Sowerby, No. XXII. 



(2) Pir. terebrans. Lam.; List., Tab. 115, f. 10; — Fir. madagascariensis, Encycl., 

 pi. 458, f. 2, a, b. Sec. 



(3) Which must be carefully distinguished itom. the. Jidseons of Oken that ap- 

 pear to be allied to the ^plysix. 



(4) Valuta tomatilis, and bifasdata, L., Martini, U, xliil, 442, 443; — V. sulcata, 

 and V. solidula, lb., 440, 441;—?^ Jlammea, Ib.,439;— Fi Jlava, lb., 444;— F". 

 pusilla, lb. 446. 



(5) Trochus dolabratus, L. Cliemn., V, clxvii, 1063, 1064; — BuUmus terebellum, 

 Brug., List., 844, 72. 



(6) This genus forms the family of the Oxtstom^e, Blalnv. 



