52 DE. T. DAVIDSON ON EECENT BEACHIOPODA. 



JFaldheimia venosa, like all its congeners, is variable in external shape. The foramen 

 is larger in some specimens than in others. As is the case with W. lenticularis when 

 quite young and sometimes until half its growth, W. venosa is either almost circular 

 or transversely oval. W. dilatata seems to be a half-grown individual with a large 

 foramen (Plate IX. fig. 1). 



IF. venosa has often been confounded with Laqnetts calif ornicus of Koch, both species 

 attaining large dimensions ; but the loop in both is entirely different, and in the last- 

 named species the beak is much more incurved, the foramen very small, and separated to 

 a greater or less extent from the umbo of the dorsal valve by a deltidium in two pieces. 



In Vol. clxviii. of the Phil. Trans., 1879 (Transit of Venus Exped.), Mr. Edgar A. Smith 

 mentions Waldhelniia {Terebratida) dilatata, Lamarck, as having been obtained at Obser- 

 vatory Bay at a depth of 4 fathoms. I may, however, remark that the ' Challenger ' 

 Expedition did not bring back a single specimen of Solander's species. 



28. "Waldheimia lenticularis, Deshayes, sp. (Plate IX. figs. 2-13.) 



Terebratula lenticularis, Deshayes, E.evue Zoologique par la Soc. Cuvierienne, p. 359, 1839, and Mag. 

 de Zoologie, d'Anatomie comparee et de Paleontologie, p. 41, figs, a, b, c, d, 1841 ; G. B. Sowerby, 

 Thes. Coucliyl. vol. i. p. 360, pi. Isxii. figs. 108-110, 184G; Davidson Ann. & Mag. Nat. Hist. 2nd ser. 

 vol. ix. p. 305, 1852; L. Reeve, Monogr. of Terebratula, Conch. Icon. pl. 2. fig. 4, I860. 



IValdheimia lenticularis, Gray & Woodward, Brit. Mus. Cat. of the Brachiopoda, p. 58, 1853 ; Dall, 

 Proc. Acad. Nat. Sci. Philadelphia, p. 182, 1873. 



Neothyris lenticularis, Douville, Bull. Soc. Geol. de France, 3" ser. t. vii., 1879. 



IValdheimia lenticularis, E. Deslougchamps, Notes sur les Modifications h. apporter jl la Classe des 

 Terebratulidae, pl. xvii. figs. 5-7, 1880. 



Shell large, orbicular, elongated oval, globose, longer than wide, thick, rounded 

 laterally, less so in front. Dorsal valve uniformly convex or slightly depressed at or close 

 to the frontal margin. Ventral valve deeper, and a little more convex than the dorsal 

 one and slightly longitudinally carinated ; beak rather sharply incurved, overlying the 

 umbo of the opposite valve, and truncated by a small circular foramen, separated from 

 the hinge-line by a wide, narrow, concave deltidium in two pieces ; beak-ridges very 

 sharply defined. Surface smooth, marked by concentric lines of growth, punctate. 

 Colour pinkish red or yellowish horny. Loop simple, long, and reflected ; cardinal process 

 rather large and prominent ; under it a mesial sejitum extends to about one third of the 

 length of the valve on either side the adductor and other muscular scars. Length 

 2 inches 2 lines, breadth 1 inch 11 lines, depth 1 inch 3 lines. 



Sal). Lives abundantly attached to rocks in the Straits of Eouveau, New Zealand, in 

 15 fathoms. It occurs also in great numbers in the Pleistocene rocks of New Zealand. 



Capt. F. W. Hutton, in his ' Catalogue of the Tertiary Mollusca of New Zealand,' p. 35, 

 1873, quotes the following localities : — " Wanganui, The Deans, Waipara, Waitotari, 

 Chatham Islands." The fossil is also well described and figured by Prof. E. Suess from 

 tlie ' Novara ' Expedition, in his fine memoir " Eossile MoUusken und Echiuodermen aus 

 Neu-Seeland," Palajontologia, p. 56, pl. x. figs. 3, 4 (18GG). 



Obs. I have in my possession a very large series of specimens of this fine species from 



