JURASSIC AND TRIASSIC BRACHIOPODA. 167 



145. Waldheimia ornithocephala, Sow. Dav., Ool. Mon., p. 40, PL VII, figs. 6, 7, 



8, 10—13, and 23; Sup., PI. XXII, 

 figs. 1,2 j PI. XXIV, fig. 27. 



Terebratula ornithocephala, Sow. Min. Con., tab. ci, figs. 1, 2 (?), (not 4), 1815. 



— TRiauETRA, Sow. Min. Conch., tab. ccccxlv, fig. 1, 1821. 



— ornithocephala, Dav. Proc. of the Dorset Nat. Hist, and Antiquarian 



Field Club, pi. iii, figs. 12, 13, 1877. 



Witli the help of Sowerby's description and the one I have given at p. 40 of my 

 Monograph the student will have a correct idea of the shell we retain as the type of the 

 species. It is very variable in shape, smooth, usually longer than wide, ovate-rhomboidal, 

 broadly rounded posteriorly, laterally and anteriorly more or less pinched in, and nearly 

 straight in front. Valves moderately convex, without fold or sinus, but flattened along 

 the middle, and somewhat abruptly sloping away laterally so as to leave two more or less 

 defined diverging lines on the surface of both valves ; the beak is much incurved, the 

 small circular foramen slightly overlies the foramen of the opposite valve, but usually 

 leaves a small space for the deltidial plates between it and the hinge-line ; loop long. 

 When adult the shell measures 1 inch 8 lines in length, by 1 inch 1 line in breadth and 

 10 lines in depth, but it is usually smaller. Some specimens which have been referred to 

 this species are almost spherical, with both valves very convex, but these cannot be 

 taken as indicating the average shape of the shell. 



Fine typical examples of W. ornithocephala have been found by Mr. J. P. Walker in 

 the cutting through the Puller's earth rock at Bruton Railway-station, Somersetshire. 

 Mr. E. Deslongchamps considers W. ornithocephala to be a tolerably well-defined species 

 occurring only in the Puller's earth ; but I very much doubt its being so localised ; and at 

 any rate Mr. Sowerby mentions having found it in the Cornbrash together with W. 

 obovata. Mr. Darell Stephens also collected characteristic specimens in the Inferior Oolite 

 at Milborne Wick, near Bradford Abbas ; but in this instance the stratum may perhaps 

 have been Fuller's earth rock. 



. Waldheimia ornithocephala occurs also round Nunney and between Whatley and 

 Prome in the Puller's earth rock. These specimens and those from Bruton are of a 

 yellowish colour. It is also found at Box Tunnel, near Bath, where the specimens are 

 of a blue colour arising from the nature of the matrix. Prom this place, perhaps, 

 Sowerby's fig. 2 may have been derived, and by mistake referred to Blue Lias j for in 

 the Puller's earth Oolite of this last-named locality all the specimens are of a bluish 

 colour, while the shell is brown in the same rock of other places, and elsewhere, again, 

 of a light yellowish tint, always due to the nature and colour of the matrix. A variety 

 of W. ornithocephala resembling W. ohovata, or its variety Stiltonensis, occurs sparingly 



