GASTEROPODA. 103 



5. RISSOA PUNCTURA (?). Mont. Tab. XI, fig. 4, a b. 



TURBO PUNCTURA. Mont. Test. Brit. p. 320, t. 12, fig. 5, 1803. 



RISSOA CONCINNA. S. Wood. Catalogue 1842. 



CINGULA PUNCTURA. Thorpe. Brit. Mar. Conch, p. xliii, 1844. 



R. Testa elongato-ovatd, turritd ; apice acuminato ; anfractibus sex, convexis; suturis 

 profundis; lineis elevatis transversis ; longitudinalibusque decmsatis; aperturd ovato- 

 orbiculari ; umbilico parvo ; labro incrassato, marginato ; intus denticulate . 



Shell elongato-ovate, turreted with an elevated spire, and about six very convex 

 volutions ; suture deep, covered with 6 8 elevated transverse striae or ridges, 

 crossed by longitudinal lines, regularly decussating the exterior ; aperture subcircular, 

 with a continuous peristome, behind which is a small umbilicus ; outer lip thickened 

 and denticulated within. 



Axis, i of an inch. 



Locality. Cor. Crag, Sutton. Recent, British Seas. 



This elegant little shell is not rare in the Coralline Crag, though the specimens are 

 often much rubbed, and the external markings nearly obliterated. Some specimens 

 show a thickened varix upon the penultimate whorl, as if the animal had occasionally 

 grown beyond the ordinary size. The punctures between the cancellations are not 

 visible in my specimens. Fleming considers T. punctura of Montague to be the 

 young of T. reticulata ; our Crag shell, from its thickened outer lip, is, I have no doubt, 

 a full-grown species. 



6. RISSOA RETICULATA (?). Mont. Tab. XI, fig. 5, a b. 



TURBO RETICULATUS. Mont. Test. Brit. p. 322, t. 21, fig, 1, 1803. 

 CINGULA RETICULATA. Flem. Brit. An. p. 306, 1828. 

 Not. EISSOA RETICULATA. Phil. En. Moll. Sic. vol. i, t. 10, fig. 14, 1836. 

 RISSOA RETICULATA. S. Wood. Catalogue 1842. 



R. Testa ovato-conicd, brevi, crassd ; anfractibus quinque, rotundatis ; longitudinaliter 

 plicatis ; transversim crassi-striatis ; striis reticulatis, nodulosis; aperturd subrotundd, 

 labro extus incrassato, intus denticulato ; labio tenui subreflexo. 



Shell small, ovato-conical, short, thick, and strong ; volutions five, convex, longi- 

 tudinally plicated or costulated ; with thick and coarse transverse striae decussating 

 the exterior ; aperture subcircular, with a thickened outer lip, dentated within ; inner 

 lip thin, rather spreading, covering the umbilicus. 



Axis, of an inch ; diameter, f the length. 



Locality. Cor. Crag, Sutton. Recent, British Seas. 



This shell has about six or seven large, coarse, and elevated transverse lines or 

 ridges, which pass over the ribs, making the exterior decussated and nodulous ; the 

 costae are vertical, and they vary in number from eleven to sixteen in the last volution, 

 becoming obsolete over the base. In the adult state, the mouth is thickened externally, 



