142 MOLLUSCA FROM THE CRAG. 



difficult to distinguish them ; and it is possible that species may have been an 

 inhabitant of the Crag Sea, but my cabinet does not contain a good or decided 

 specimen, and this may perhaps be considered as its representative. Fig. 10 c 

 shows the coarse strias in the umbilicus. 



2. Natica catena. Da Costa. Tab. XVI, fig. 8, a — b. 



Cochlea catena. Da Costa. Hist. Nat. Test. Brit. p. 83, t. 5, fig. 7, 1778. 

 Nebita glaucina. Mont. Test. Brit. p. 469, 1803. 

 Natica Britannica. Leach. MS. 1818. 



— monilifeea. Lam. Hist, des An. sans Vert. 2d edit. torn, viii, p. 638, 1838. 



— Nicolii. Forbes. Malac. Mon. p. 30, 1838. 



— glaucinoides (?). Ntjst. Coq. foss. de Belg. p. 442, pi. 37, fig. 32, 1844. 



— catena. S. Wood. Catalogue 1842. 



N. Testa ventricoso-globosd, laevigata, politd ; spird prominuld ; anfractibus 5 — 6, 

 convexis, super ne depressicuscidis ; aperturd ovatd, sub recta ; umbilico aperto. 



Shell ovato-globose, smooth, and glossy, with a short but distinctly produced 

 spire ; whorls 5 — 6, convex, somewhat flattened above, with a deep suture ; aperture 

 ovate ; umbilicus open and deep ; left lip slightly spreading, and rather callous below. 



Longest diameter, \\ inch. 



Locality. Red Crag, Sutton. 



Mam. Crag, Bridlington. Recent, British Seas. 



This shell is not so abundant as the preceding; but I have at least a dozen 

 specimens in good preservation, and they correspond so precisely with the recent 

 British species that there is little doubt of the identity. This differs from the 

 preceding species in having the volutions more convex and distinct, with a more 

 elevated spire, and it is not so large. These shells are also somewhat altered by 

 decortication, more especially at the suture ; but some specimens have portions 

 which sufficiently show the original form, and with a diameter of only half that of 

 the preceding species, they have as many volutions. 



" This species is found buried in sands at very low tides in the Frith of Forth." 

 (Forbes's Mai. Monensis, p. 30.) 



3. Natica Guillemini (?). Payraudeau. Tab. XVI, fig. 1, a — b. 



Natica Guillemini. Payr. Cat. des Moll, de l'lle de Corse, 1826, p. 119, pi. 5, fig. 25-26. 



— Desk. 2d edit. Lam. vol. viii, p. 648, 1838. 



— Phil. En. Moll. Sic. vol. i, p. 162, 1836. 



— [- - - vol. ii, p. 140, 1844. 



TV. Testa ventricoso-ovatd, glabra ; spird prominuld, acutiusculd ; anfract'ibus quinque 

 convexis, subdepressis ; umbilico parvo, subnudo ; labio adnato, catloso. 



Shell ventricosely-ovate and smooth, with a slightly prominent spire, and rather 

 acute apex ; volutions five, depressedly rounded ; and a small umbilicus, partly 

 hidden by the lower portion of the callous and reflected left lip. 



