213 PERMIAN FOSSILS. 



of my specimens, of which I collected several, display the least indication of a slit in 

 the outer lip Its flattened apex, and rather large umbilicus, are characters readily 

 separating it from any of the Gasteropods next to be described. 

 It is rathoi common in Shell-limestone at Tunstall Hill. 



>: 

 Family NATiciDiE, Forbes, 1838. 



The animal of this family is " peculiar for having a large foot, in which the hemi- 

 spherical shell is imbedded, and which is much produced in front, beyond its edge : 

 the tentacles are small, sometimes obliterated, and the mouth is hid in a groove : the 

 operculum is spiral."^ 



Genus Natica, Adanson, 1757. 



Diagnosis. — " Shell generally thick, strong, smooth, and glossy, occasionally covered 

 with fine striae, of an ovate, globulous, or subspheroidal form, with a short or slightly 

 elevated spire ; aperture oval, or semilunate ; outer lip plain and simple ; inner 

 lip sometimes depositing a callosity, the callus modifying the form and size of the 

 umbilicus." (Searles Wood.^) 



Natica minima. Brown. Plate XVI, fig. 29. 



Natica minima, Brown. Trans. Manch. Geol. Soc, vol. i, p. 64, pi. vi, figs. 22-24, 1841. 



— — „ Morris, Catalogue, p. 153, 1843. 



— — „ De Verneuil, BuU. Soc. Geol. deFrar\ce, 2'"^serie, vol. ij p. 34, 



1844. 



— — „ Geol. Russ., vol. i, p. 225, 1845. 



— — „ Tennant, Strat. List, p. 89, 1847. 



Diagnosis. — " Shell ovate ;. body large ; spire small, consisting of two depressed 

 volutions ; aperture semilunar." (Brown.^) 



This very minute species, the typical specimen (a rather imperfect cast) of which 

 does not exceed one sixteenth of an inch in height, was found by Mr. E. W. Binney in 

 the Permian Marls near Manchester. 



Natica Leibnitziana, King. Plate XVI, figs. 27, 28. 



Natica Leibnitziana, King. Catalogue, p. 13, 1848. 



LiTTORtNA minima (Natica ID.), Brown. Howse, Trans. T. N. F. C, vol. i, p. 240, 1848. 



Natica Heecyntca, Geinitz. Versteinerungen, p. 7, pi. iii, figs. 11-13, 1848. 



Diagnosis. — As wide as it is high : rather thick : marked with zig-zag coloured 

 bands in the direction of the incremental laminae, which are oblique to the axis of the 



1 Gray, Synopsis of the Britisli Museum, p. 91, 1841. 



2 Monograph of the Crag Mollusca, parti, p. 140. 



3 Trans. Manchester Geol. Soc, vol. i, p. 64, 1841. 



