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 1812. 



Cingula punctura. Thorpe. Brit. Mar. Conch, p. xliii, 1844. 



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

 profundis; lineis etevatis transversis ; longitudinalibusque decussatis j aperturd ovato-orbi- 

 culari ; timbilico parvo ; labro incrassato, marginato ; intus deniiculato. 



Shell elongate-- 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 subcir- 

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

 thickened and denticulated within. 



Axis, \ 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 speci- 

 mens show a thickened varix upon the penultimate whorl, as if the animal had occa- 

 sionally 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. 30G, 1828. 

 Not. Rissoa reticulata. Phil. En. Moll. Sic. vol. i, t. 10, fig. 14, 1836. 

 Rissoa reticulata. S. Wood. Catalogue 1842. 



It. Testa ovato-conicd, brevi, crasm ; anfractibm quinque, rotundatis ; longitudinal/ ter 

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

 labro extus incrassato, intus deniiculato ; labio tenui subreflexo. 



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

 tudinally plicated or costulated ; with thick and coarse transverse strige decus- 

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

 within; inner lip thin, rather spreading, covering the umbilicus. 



Axis, Y5 of an inch ; diameter, | 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, with a large and prominent obtuse varix, and there are 

 about eight denticulations within the outer lip. 



