530 Mr. S. V. Wood's Catalogue of Shells from the < rag. 



Cor. Crag. Red Cray. Mam. Cray. Recent. 



9. Natica proxima, n. s. 



Ramsholt. | | | 



10. — depressula, n. s. ? 



Sutton. | | | 



Not more than one-eighth of an inch. Three specimens of this 

 small shell, which I cannot affiliate to any of my crag species, although 

 I have many young specimens quite as minute ; however, till more 

 be found, it must be considered doubtful. 



Natica depressa, Min. Con. t. 5, is probably a French shell, or from 

 the Isle of Wight, figured by mistake as from the crag. 



An abundance of individual specimens are found, especially in the 

 red crag ; but the labour of identification is great, from the difficulty 

 of procuring specimens that are not more or less altered by decom- 

 position, or rather decortication, many having the outer covering en- 

 tirely removed, showing in some instances a striated surface upon a 

 shell which in its natural state is perfectly smooth ; and in most of 

 the species of this genus a deep depression is visible at the suture 

 when the exterior coating is removed, which materially alters the 

 appearance of the shell. 



1. Adeorbis (n. g.) striatus, mihi. 



Sutton. | | | 



Gen. Char. Whorls subdiscoidal, volutions few, peritreme sharp, 

 inner lip sinuous, umbilicus large and deep. 



Spec. Char. Shell depressed ; volutions four, rounded, slightly im- 

 pressed by the preceding whorl, spirally striated ; outer lip sharp, 

 projecting; inner sinuous; umbilicus large, open, volutions visible to 

 the apex. Diameter one-seventh of an inch. PL V. f. 4 and 6. 



There is an incipient sinus in the upper part of the aperture, which 

 gives in one of the species particularly (supra-nitida) a depression at 

 the upper part of the volution at a little distance from the suture. 



I consider this distinct from Skenia in the form of the peritreme, 

 which, in that genus, is circular and not sinuous. 



2. Adeorbis supra-nitidus, n. s. 



Sutton. | | | 



3. — tricarinatus, n. s. 



Sutton. | | | 



4. — subcarinatus (Helix subcarinata, Mont. Test. Brit. p. 438. pi. 7. 



f. 9. Trochus subcarinatus, Brown, Conch. Illust. pi. 51. 

 f. 16, 17). 



Sutton. | | | Britain. 



5. — ? subimbricatus, n. s. 



Sutton. | | | 



1 . Margarita helicina, n. s. 



Sutton. | | | 



2. — trochoidea, n. s. 



Sutton. | | | 



1. Scissurella crispata ? Flem. (Brit. An. p. 366). 



Sutton. | | | Britain. 



