180 MOLLUSCA FROM THE CRAG. 



is not such as to permit of correct description, but it does not appear to correspond 

 with the "fasciis binis incrassatis " of M. Loven. Mr. Alder informs me that this 

 species has been found in a living state upon the coast of Northumberland. A 

 slight contraction in the upper part of the volution takes from the otherwise nearly 

 quadrate contour of the shell. 



2. Bull^a sctjlpta. S. Wood. Tab. XXI, fig. 10, a — c. 



Bulla catenata. S. Wood. Illust. in Mag. Nat. Hist. p. 460, pi. 7, fig. 2, 1839. 

 BuLLiEA sculpta. S. Wood. Catalogue 1842. 



B. Testa pusilld, ovatd, tenui, fragili ; anfractibus superne coarctatis, densissime striatis ; 

 striis diver gentibus, sculptis, cateniformibus ; spird depressd, vix distinctd ; aperturd 

 patente, labio acuto prominente, umbilico parvo. 



Shell small, ovate, thin, and fragile ; volutions slightly contracted round the 

 upper part ; spire depressed, scarcely visible ; covered externally with diverging 

 chain-like strise ; outer lip curved ; inner lip sharp and prominent, with a small 

 umbilicus ; muscular impression slightly visible. 



Axis, ^ ; diameter, \ of an inch. 



Locality. Cor. Crag, Sutton. 



Only two or three specimens of this elegant shell have as yet come into my pos- 

 session, and these appear somewhat to resemble B. catena, Montague ; but a specimen 

 of the latter, obligingly sent to me by Mr. Alder, differs in the following characters : 

 — it has a wider aperture, is less convolute, more quadrate, or more expanded, in 

 the lower part of the outer lip, and wants the inflected and prominent portion of 

 the inner lip ; a large series of both species might, perhaps, show a greater resem- 

 blance, but there is sufficient difference in the specimens I possess to justify their 

 being considered as distinct. Bulla punctata, Adams, Lin. Trans, v. t. 1, f. 6 — 8, is 

 stated by Dr. Turton, Mag. Nat. Hist. 1834, p. 353, to differ from B. catena in 

 having distinctly-impressed dots upon its surface, instead of oval, raised, chain-like 

 stria?, which form the lines in B. catena, and the animal is said to be destitute of a 

 gizzard. Our shell is covered with regular chain-like strise, similar to those upon 

 B. catena, and was, no doubt, white and semi-transparent in its recent state. 



