RETUSA. 205 



H. TRUNCATULA Bruguiere. PL 21, figs. 11, 12 ; pi. 23, figs. 62-64. 

 Shell forming a conical cylinder, narrow on the upper half, more 

 or less deeply constricted in the middle, and expanding on the lower 

 half; it is nearly opaque and glossy: sculpture numerous longitu- 

 dinal striae or fluted ribs on the upper half; these are often sharp 

 at the apex, not so distinct in the middle of the shell, and usually 

 disappear towards the base, where they are replaced by lines of 

 growth; the spire is frequently striated across, like an Ammonite; 

 epidermis filmy ; color white ; spire involute, abruptly truncated, 

 and encircled by a narrow arid solid rim or rounded keel ; whorls 3 

 4, gradually decreasing in size towards the center of the apex ; the 

 first or innermost whorl is globular ; suture deep ; mouth narrow for 

 more than half its length on the upper part, pear-shaped and very 

 wide at the base, which is rounded : outer lip gently curved and 

 folded inwards in the middle ; the upper part projects (sometimes 

 considerably) beyond the apex; outer corner rounded ; inner corner 

 receding and obliquely incurved ; inner lip slight, continuous with 

 the outer lip above, where it is folded a little over the apex, as well 

 as over the pillar, behind which it forms a small and narrow um- 

 bilical chink ; pillar short, thick, and flattened : fold tooth-like and 

 -strong (Je$r.). 

 Coast of Norway to the Canaries ; Mediterranean and Adriatic Seas. 



Sulla truncatula BRUG., Encycl. Meth., p. 377, 1792. Utriculus 

 truncations JEFFR., Brit. Conch., iv, p. 421, pi. 94, f. 2. SARS, 

 Moll. Reg. Arct. Norv., p. 285, pi. 26, f. 2 ; pi. 17, f. 18 (var. pellu- 

 cida). Retusa truncatula BUQ., DAUTZ. & DOLLF., Moll. Rouss., 

 i, p. 527, pi. 64, f. 12-14. Bulla truncata AD. (not Gmelin), Tr 

 Linn. Soc., v, p. 1, pi. 1, f. 1, 2. Volvaria truncata BROWN, 111. 

 Conch., G. B., Ed. 1, pi. 19, f. 17, IS. Cylichna truncata LOVEN, 

 Ind. Moll. Skand., p. 42. FORBES & HANLEY, Hist. Brit. Moll., 

 iii, p. 510, pi. 114, f. 7, 8; pi. vv, f. 4 (animal). MEYER & 

 MOBIUS, Fauna der Kieler Bucht, i, p. 87 (animal). Bulla retusa 

 MATON &RACK., Descr. Cat. in Trans. Linn. Soc., viii, p. 128, 1804. 

 Retusa obtusa BROWN, Pop. Encycl., ii, p. 78, pi. 17, f. 110. 

 Volvaria pellucida BROWN, 111. Conch. G. B. Edit. 1, p. 4, pi. 19, 

 f. 45, 46. Utriculus truncatulusvar.pyriformis MONTS., Nom. Gen. 

 e Spec., p. 50. 



