562 J. F. Walker — L. Greensand Brachiopoda. 



this species, which measures, length 0-23 in., breadth 0*2 in., thick- 

 ness 0'13 in. 



Waldheimia mutahilis, var. W. elUptica. — The largest specimen I 

 have of this species measures, length 1-7 in., breadth 1-3 in., thick- 

 ness 0'65 in. 



Waldheimia pseudojurensis. — This species has its deltidium in two 

 pieces. Loop long. In Vol. V., PI. XVIIL, the deltidium was 

 figured in one piece by mistake. 



Waldheimia rhomboidea. — Mr. Davidson kindly informs me that 

 this name has been given to an Italian Tertiary shell by Biondi in 

 1855, and its name requires to be changed. I have therefore much 

 pleasure in naming it W. Juddii, in honour of J. W. Judd, Esq., 

 F.G.S. 



Terehratula sella, figured in GtEologioal Magazine, September, 1868. 

 — This specimen differs from the typical form, and somewhat ap- 

 proaches specimens of T. Carteroniana (D'Orb.). Mr. Davidson thinks 

 that it ought to be distinguished as a variety — T. sella, var. T. 

 JJpiDarensis. Shell globular, deeply plicated, sides of the shell 

 compressed, surface smooth, marked by faint concentric lines of 

 growth ; ventral valve very much recurved, the deep plications ex- 

 tending about two-thirds of the length of the valve, forming a 

 centi'al elevation on eadi side of it, and a deep depression, again 

 rising into an elevation, thence bending at right angles, it forms the 

 flat side of the shell ; the upper third of the shell is somewhat con- 

 vex, the beak curved, short, truncated by a large round foramen, 

 the margin of which is thickened at the sides ; beak ridges rounded, 

 deltidium in one piece, shallow and wide ; dorsal valve irregularly 

 round in shape, upper two-thirds nearly flat, lower (front partj 

 deeply plicated, having a deep groove in the centre, bounded on each 

 side by an elevation, then a wide depression which slopes to meet 

 the lateral elevations of the ventral valve, thence rising to the level 

 of the flat part of the valve, where the shell has its greatest width. 

 Loop short. Average dimensions : length 1-1 in., breadth, 0*9 in., 

 thickness, 0-8 in. 



Besides the specimens described in this and my previous papers, 

 there are found at Upware and at Potton, derived specimens of a 

 large Terehratula, which has been referred by Mr. E. E. Lankester 

 to T. rex. These specimens vary very much in form and dimensions. 

 There are also found, both at Upware and Potton, derived specimens 

 of two or three species of Ehynchonella, the species of which I have 

 not yet been able to determine. 



I have found at Farringdon, Berkshire, in the sponge gravel, a 

 specimen of T. prmlonga, which species also occurs at Upware, and 

 in the Lower Greensand of the South of England. 



Ehynchonella Crossii, Fig. 9. — Shell wider than long, smaller valve 

 convex with about fourteen plaits on its surface ; the plaits are covered 

 by spines, the three central plaits are elevated ; the larger valve is 

 depressed in the centre, having a wide fold formed of four plaits ; 

 the number of plaits on this valve is about fourteen, which are also 

 covered by spines ; the beak is recurved. Length 0-3 in., breadth 

 04 in., thickness 0-25 in. 



