146 



front ; interior unknown. Peduncular valve as deep as tlie 

 opposite valve ; beak large, incurved, and obliquely truncated 

 by a large obovate foramen. 



Surface smooth, marked by moderate lines and stria? of 

 growth. 



Dimensions. — Length, 1\S ; breadth, 1*35 ; thickness, 1'3 inch. 



Locality and Horizon. — In the coarse limestones forming the 

 low sea-cliff on the south side of the jetty at Editbburgh, 

 Yorke's Peninsula. (One example). 



Waldheimia G-aribaldiana, Davidson. Plate xi., figs, la— U. 



Bef.— Geologist, vol. v., p. 446, t, 24, f. 9, 1862. 



Id. R. Etheridge, jun., Ann. and Mag. Nat. Hist., vol. 

 17, p. 17, t. 1, f. 2, 1876. 



Syn. — Terebratula sp., Sturt. Two Expeds. in S. Aust., 

 vol. ii., t. 3, f. 15, 1834. 



Terebratula compta, Woods. Geol. Obs. in S. Aust., p. 74, 

 wdct., 1862 (non Sow). 



Waldheimia imbricata, Woods. Proc. Phil. Soc, Adelaide, 

 fig. 3, 1865 ; and Trans. Eoy. Soc. of K.S.W., p. 79, f. 1, 1878. 



Waldheimia macropora, McCoy. Prod. Pal. of Victoria, 

 decade v., pi. 43, figs. 4 and 6, 1877. 



W. imbricata, W. G-aribaldiana, and W. macropora, 

 Etheridge. Cat. Aust. Eossils, 1878. 



W. Garibaldiana is the commonest palliobranch in the middle 

 beds of the River Murray cliffs, and exhibits some slight 

 variation of form and ornament, more particulaxny in respect 

 to age. The example figured by Etheridge is exceptionally 

 large, and is more angular in outline and more deeply sulcated 

 than the majority of adult specimens which I have seen. In 

 its adolescent stage of growth, which is represented by Sturt' s 

 figure, the outline of shell is more or less circular, with 

 slightly convex valves, which are fimbriated ; but the front is 

 not depressed, nor is there an appearance of biplication. 



The form varies from nearly circular to ovate ; and the 

 pentagonal outline, though never obscure in the adult, varies 

 in its angularity, and in the depth of the sulci exhibits much 

 variation, as also the height and number of ribs. The medial 

 depression is occupied with from three to six longitudinal ribs, 

 and the lateral portions of the valves have usually about ten 

 curved ribs on each side. 



The loop is that of a Waldheimia reaching nearly to the 

 front in a gentle curve, the reflected portion approximating to 

 the long slender erect cruras which are rather distant from the 

 hinge plate. 



The shell structure is conspicuously punctate as viewed with 

 a pocket lens. The pores are large circular, but not so 



