166 



Locality and Horizon. — In the glauconitic limestones Blanche 

 Point, Aldinga Bay. Nine examples. 



Thecidium australe, *pec. nov. Plate ix., figs. 3a— 3c. 



Shell minute, one-eighth of an inch in diameter, triangular- 

 ovate, inequilateral, attached by the umbonal surface of the 

 peduncular valve. Surface smooth, conspicuously punctate, 

 and ornamented by a few thick folds of growth. 



Brachial valve flattish ; hinge line straight, but interrupted 

 in the middle by a small subquadrate cardinal process ; interior 

 unknown. 



Peduncular valve, inflated and produced at the umbo, which 

 is obliquely truncated by the surface of attachment ; interior 

 with coarse radial stria?, which crenulate the thin margin. 

 Hinge teeth prominent. Within the umbonal cavity is a cup- 

 shaped cavity for the attachment of the adductor muscles, 

 divided longitudinally by a septum, which is continued half as 

 far again beyond it. 



This notice is, I believe, the first record of the occurrence of 

 the genus, either recent or fossil in the southern hemisphere. 



Locality and Horizon. — In the Miocene strata at Muddy 

 ■Creek, from which I obtained one perfect shell and four 

 peduncular valves. 



Rhynchonella squamosa, Hutton. PI. ix., figs. 9a— 96. 



Ref— Cat. Tertiary Mollusca of New Zealand, p. 37, 1873. 



Syn. — Rhynchonella coelata (McCoy, MS.), Woods, Trans. 

 Eoy. Soc, N.S.W., p. 77, 1878. 



Rhynchonella lucida, McCoy, M.S. (jion Gould, 1860). 



"Shell irregular, more or less orbicular ; valves inequal, the 

 ventral flatter with a deep groove ; dorsal valve very convex ; 

 both with fine radiating scaly stria?. Length, "7 ; breadth, "75 ; 

 height, 5. Easily distinguished from R. nigricans by its more 

 numerous stria?." — Hutton. 



Remarks. — The task of establishing a correct synonym of 

 manuscript names is one that is very properly unattempted by 

 monographers ; but in this instance the manuscript names of 

 McCoy have a fictitious value from the fact that they have been 

 published with such remarks as may lead up to their identifica- 

 tion. The Rhynchonella found at Table Cape, Tasmania, was 

 pronounced \>y Tenison Woods (Trans. Roy. Soc. Tasm., p. 15, 

 1874) to be identical with R. lucida of McCoy, common in the 

 Geelong Miocene beds ; subsequently we find the same author 

 (Trans. Roy. Soc, N.S.W., 1878) referring to it as R. coelata, 

 McCoy. Doubtless the two names have been given to the same 

 shell ; and it is probable that the change of denomination was 



