26 THE BEACHIOPODA. 



Palsoontographical Society's Journal Supplement, plate xxv., 

 fig. 2, should be taken. The other specimen figured under this 

 name (figure 1) is merely the large adult form of Tereb. perovalis, 

 and not a variation, Tereb. ampla is really so distinct from the 

 ordinary type of Tereb. perovalis in all its stages that it would 

 almost seem to warrant its separation as a species, and probably 

 if more good specimens were collected its characters might be 

 well enough defined for it. Its distinguishing characters are 

 Breadth nearly always greater than the length. Margin very 

 sharp and without plications, but having only one slight bend. 

 Beak rather small and round. What we take for the young 

 of Tereb. ampla answer to this description. They are very 

 distinct from Tereb. perovalis, but are connected by the Cottes- 

 wold form figured in Mr. Davidson's supplement, plate xviii., 

 fig. 2. They almost exactly resemble Tereb. Whitakeri (Walker), 

 Davidson, Supplement, plate xix., figs. 6-9, some of them hav- 

 ing the bend shewn, while others have the margin quite straight. 

 From the Oolite Marl near Salperton, Gloucestershire, I collected 

 many specimens, which are exactly the same as our young Tereb. 

 perovalis, var. ampla, and some of them have the fold which 

 characterises Tereb. Whitakeri. Anyway Tereb. WhitaJceri and 

 our young Tereb. ampla seem to me to be one and the same 

 species. They might possibly be distinct from the adult 2ereb. 

 perovalis var. amply,, figured by Mr. Davidson, but do not seem to 

 be so. This adult Tereb. ampla seems to be connected with Tereb. 

 perovalis by a shell which is longer than broad, base slightly 

 thickened, and just showing two plications. This is most prob- 

 ably the shell figured by Bayle, plate vi., fig. 1, and should 

 certainly be classed with the variety T. ampla. It is possible, as 

 I observed before, that if more specimens of the large Tereb. 

 ampla were collected its differences could be defined sufficiently 

 well to warrant its being made a distinct species. 



Localities. Bradford Abbas, &c. (Dorset), near Gorton and 

 Haselbury (Somerset), and Cotteswolds (Gloucestershire). 



