142 MOLLUSCA FROM THE CRAG. 



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 striae in the 

 umbilicus. 



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



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

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

 Natica Britannica. Leach. MS. 1818. 



— MONiLiFERA. La7n. Hist, des An. sans Vert. 2d edit. torn, viii, p. 638, 1838. 



— NicoLii. Forbes. Make. Mon. p. 30, 1838. 



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



— CATENA. S. Wood. Catalogue 1842. 



N. Testa ventncoso-(/lohosd, lamgatd, poUtd ; spird prominidd ; anfractibm 5 — 6, 

 convexis, superne depressiusculis ; aperturd ovatd, suhredd ; 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. 



Lont^ est diameter, Ij inch. 



Locality. Red Crag, Sutton. 



Mam. Crag, Bridhngton. 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 (?). Pai/ratideau. Tab. XVI, fig. \,a — b. 



Natica Guillemini. Paijr. Cat. des Moll, de I'He 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. 



N. Testd ventricoso-ovatd, glabrd ; spird prominuld, acutiusculd; anfractibus quinque 

 convexis, subdepressis ; uvibilico jjarvo, subnudo ; labia adnata, calloso. 



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. 



