GASTEROPODA. 157 



margin forwards. The aperture is generally longer than it is wide, sometimes twice 

 as long ; a few distorted specimens, however, have the aperture transverse. In its 

 young state, the volution of the vertex is on a level with the margin, projecting 

 beyond it ; and this character is sometimes preserved throughout its existence, 

 though, in some large specimens, the vertex is elevated considerably above the level 

 of the base. It is covered with coarse and prominent strige, amounting almost to 

 ribs, with deep sulci between them, and occasionally decussating lines of growth, 

 which are, however, very irregular, and not always visible. The muscular band 

 appears like that in C. ungaricus, but in my specimens it is not always distinct. 



Small and imperfect specimens are by no means rare in the Coralline Crag. 

 In Capulus ungaricus the vertex is generally regular and straight, though occasionally 

 it may be observed to incline on one side. This species appears to have a longer 

 cone, with the vertex always on the right side. The sinuses in variety /3 appear as 

 if they had been produced by the inequalities or rays of a pecten, upon which the 

 animal might have adhered. In my specimens (only three in number) they are upon 

 the left side of the shell, and regular, and if produced in this manner, the animal 

 must have had the power to elevate its right side so as not to be similarly affected, 

 as that side is free from these inequalities ; the strias upon the exterior take a longi- 

 tudinal or rather a radiating direction from the vertex, and run obliquely across 

 these sinuses, from which it is presumed they are accidentally produced. 



4. Capulus fallax. S. Wood. Tab. XVII, fig. 4, a — b. 



Capulus fallax. S. Wood. Catalogue, 1842. 



C. Testa suborbiculatd, depressd, laevigata, tenui, fragili ; vertice obliquissime ad 

 dextram revotuto, spiraliter intorto ; margine postico {///pendente ; basi dilatatd, subovatd. 



Shell suborbicular and depressed, smooth (?), thin, delicate, and fragile, with an 

 involute and very oblique vertex, spirally twisted on the right side, and projecting 

 beyond the base, with an expanded subcircular opening. 



Diameter of aperture, \ an inch. 



Local ilg. Cor. Crag, Sutton. 



I have about a dozen specimens of this shell in my cabinet, which, however, are 

 not very perfect, but appear to differ from any of the preceding species sufficiently to 

 be considered distinct ; they are perfectly smooth, without strige, but they are much 

 injured, and cannot be depended upon iu that character. The great obliquity of 

 volution, which much exceeds that of C militaris, is the character which best dis- 

 tinguishes it, and gives it a form approaching to the genus Velutina. Unfortunately, 

 I have no specimen that will show its muscular impression, but the flattened form 

 of the posterior margin, beneath the vertex, sbows the capuloid character of the 

 shell ; this obliquity of its volutions gives it a subcarinated form to the left side of 

 the back, and connects this species with the regularly but obliquely spiral univalves. 



