147 



numerous as in W.fiavescem in the proportion of about five to 

 eight. 



Dimensions. — A senile example : length, 1'75 inch ; breadth, 

 1/5 iuch ; depth, 1 inch. 



The specimen figured by Mr. Etheridge, another aged form : 

 — Length, 1/5 ; breadth, 1*25 ; depth, - 8 inch. 



A rather large example, in which the diverging ribs of the 

 peduncular valve and the arched front have not acquired 

 prominence, has length, 1*2, breadth 1*0, depth 075 inch. 



Alliance. — W. Oaribaldiana bears some resemblance to W. 

 flavescens, now living off the eastern and southern coasts of 

 Australia ; but as pointed out by Mr. Davidson, is less ovate, 

 the beak is less elongated, and it has a smaller foramen ; and 

 to which differences has been added by Prof. McCoy that of 

 the very much larger pores of the test of the fossil species. In 

 its adult state W. flavescens never acquires that remarkable 

 development of the frontal sinus and longitudinal ridges 

 observable in all aged examples of W. Garibaldiana . 



Observations. — Mr. E. Etheridge, jun., is evidently wrong in 

 referring Sturt's terebratulid to Terebratella compta, as Sturt's 

 figure represents a fimbriated shell, and in other respects is 

 totally unlike T. compta. The error is traceable perhaps to 

 Mr. "Woods, who reproduced Sturt's figure, and applied to it 

 the name of T. compta ; a rectification was, however, made by 

 him a few years later, when he described it as a new species 

 under the name of Waldheimia imbricata. Though he does not 

 refer to the figure in his " Geological Observations," nor to 

 Sturt's, yet as the drawing which accompanied his paper in the 

 Transactions of the Philosophical Society of Adelaide seems to 

 be a reproduction of one or the other, there cannot be a doubt 

 that Sturt's terebratula and "Woods' Waldheimia imbricata 

 belong to the one species. 



That W. imbricata, Woods, is a young example of W. Gari- 

 baldiana, Etheridge, is an opinion formed after the examination 

 of many score of specimens of the species, ranging from less 

 than one-third inch in diameter to more than one and a half 

 inches in diameter. W. macropora, McCoy, is a somewhat 

 intermediate form. 



I have selected from a large series collected from the same 

 stratum at Blanchetown three specimens (pi. xi., figs, la — lc), 

 which illustrate as many stages of growth, and to which the 

 names of W. imbricata, W. onacropora, and W. Garibaldiana 

 have been respectively applied. 



The shell, which Mr. Woods has figured (Trans. Roy. Soc, 

 N.S.W., p. 79, fig. 2) as the young of this species, differs not- 

 only in its well-developed longitudinal ribs from juvenile 

 examples of W. Garibaldiana, but seems rather to have the 



