ON NEW BRACHIOPODA. 171 



centric llnes of growth whicli are slightly plicatecl, givlng 

 to the shell a wi'inkled surface. 



It is from tlie Inferior Oolite of Dundry, and is the only 

 species known in that formation. It appears to be rare ; 

 for after a lengtliened examlnation of tliese beds, I have 

 only succeeded in obtalning tbree specimens. 



DisciNA ORBicuLAras, Moore. 

 PI. II., figs. 16-18. 



Shell small, orbicular, tapering to an elevated apex, 

 givlng the shell a somewhat conlcal form; margin smooth 

 and rounded. Oater surface of valve smooth, with 

 numerous concentric lines of growth; the inner smooth, 

 and very concave. 



Obs. — This shell does not appear to have attained a 

 larger sizs than is indlcated in pl. II., fig. 18. It is from 

 the fish-bed and the clays associated therewith in the 

 Upper Lias of Ilminster. By its form it is readily dis- 

 tinguished from any other species. 



DisciNA TowNSHENDii, Forbes. 

 A very fine specimen of this shell, belonging to the 

 Museum of Economic Geology, was figured by Mr. 

 Davidson in the volume of the Palasontographical Society 

 for 1850. Its locality was then uncertain, though Mr. 

 Davidson was informed it was from the Oxford Clay. 

 Subsequently it was suspected to be from one of the lower 

 beds of the Lias, Having discovercd the species in the 

 " Avicula contorta zone" at the base of the Lias, near 

 Taunton, I am enabled to settle its position. M. Edward 

 Suess, of Vienna, has informed me that he has also obtained 

 the shell in the Ehaatic beds of Austria, in which the 

 "Avicula contorta zone" is included. 



