368 PE0T0CAEDIX7M. 



Genus PROTOCARDIUM, Beyrich. 

 [Menke's Zeitsch. Malakozoologie, 1845, pp. 17-20.] 



Distinguished from Cardium in being more globose, but especially 

 by the character of the surface ornament, which, typically, con- 

 sists of radiating costse posteriorly, and tine concentric lineations 

 abutting against them on the remainder of the surface. 



Tijpe. — Cardium hillanum., Sowerby. 



Protocardium antisemigranulatum, M'Coy (sp.). 



1877. Cardium [Protocardium) antisemigranulatum, M'Coy, Prod. Pal. Vict. 



dec. V. p. 16, pi. xUv. figs. 2, 3. 

 1887. Cardium antisemigranulatum, Tate, Trans. Eoy. Soc. South Aust. 



vol. ix. p. 152. 

 1893. Cardium antisemigranulatum, Tate and Dennant, id. vol. xvii. pt. 1, 



p. 225. 



Posterior costse partly tuberculate, remainder of surface smooth, 

 but bearing minute concentric and radial striae ; margin crenulated. 

 Dhnensions. — Height 30 mm. ; length 32 mm. 

 Form, and Loc. — Eocene : Muddy Creek, Victoria. 



L. 10026. Right valve of the neanic stage of growth. Purchased. 

 Protocardium hemimeris, Tate (sp.). 



1887. Cardium, hemimeris, Tate, Trans. Roy. Soc. South Aust. vol. ix. p. 153, 

 pi. xiv. figs. 2a-c. 



Shell subglobose ; umbones much elevated; "the anterior half 

 of the surface of the valves is ornamented by numerous regular, 

 equal, flat riblets, crossed by finer and closer concentric threads 

 . . ; the intersection of the riblets and the lirse produce 

 a tesselated ornament. The posterior half is ornamented with 

 about fifty flat, narrow riblets, closely beset with small tubular, 

 conical spines." — Tate. 



Dimensions. — Height 8"5 mm. ; length 8'5 mm. 



Form, and Loc. — Eocene : Aldinga, South Australia. 



L. 9867. Several examples of both valves. Purchased. 



