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GASTEROPODA OF THE INFERIOR OOLITE. 



flattened at the periphery, but more or less pinched in anteriorly, usually provided 

 with two tubereulated marginal heels. Aperture quadrangular. 



As a rule in the species referred to Straparollus, the shell, even when there is 

 no salience of the spire, is proportionately higher than in Discohelix. All the 

 forms are rare. 



248. Discohelix Cotswoldi^e, Lycett, 1850. Plate XXV, fig. 7. 



1850. Solabium Cotswoldi^;, Lycett. Ann. Mag. Nat. Hist., 2nd ser., vol. vi, 



p. 419, pi. xi, fig. 2. 



1853. — — Prot-. Cotteswold Nat. Club, vol. i, 



p. 80, pi. ii, fig. 2. 



1854. — — sp. Morris. Catalogue, p. 279. 

 1857. — — Lycett. Cotteswold Hills, p. 40. 



Description 



Diameter (large size) . . . .12 mm. 



Height . . . . .4 mm. 



Shell discoidal, depressed, upper and under surfaces nearly equally excavated, 

 but there is some difference in this respect, and also in the relative height of the 

 specimens. Diameter ranges from 6 to 12 mm. The sides of the whorls are 

 rather flattened, but having the margins rounded off ; these latter are furnished 

 both on the upper and under surface with numerous nodules of moderate size, 

 rather close together. The smaller specimens show richer ornamentation than 

 the larger ones, and in some specimens (like the one figured) there is a tendency 

 for the nodes to die out towards the aperture. 



All the whorls are ornamented by fine wavy spiral lines, and in the body- 

 whorl this feature prevails both above and below and on the flank. Aperture 

 quadrangular, spiral and axial diameters nearly equal. 



Relations inn! Distribution. — There is considerable variety in the shells referred 

 to Discohelix Gotswoldix. Moreover, in many instances, the specimens are by no 

 means well preserved. Consequently we may in fact be dealing with more than 

 one species. Morris suggested that Solarium Cotswoldise might be identical with 

 Eiioinphal u.s tuberculosa*, Thorent ; but the differences are very considerable, as 

 may be seen further on. Doubtless most of these forms are merely local varieties 

 of some other form, but, on the whole, Discohelix Gotswoldise is sufficiently distinct 

 from anything hitherto described to be entitled to rank as a separate species. 



It occurs chiefly in the Oolite-Marl and Freestones of the Nailsworth district. 

 I have small specimens from Crickley. Lycett also quotes it from Leckhampton. 



