156 Fossils from Australia. 



the muscle ; large anterior somewhat excavate, without vertical striae,* 

 small anterior obliquely excavate ; palleal impression not very distinct. 

 Cast with antero-lateral surface of beak strongly flattened in two parallel 

 planes, that adjoining the anterior muscular impression a little concave. 



Length of cast l£ inch ; height -^ L ; thickness -^ L ; apical an- 

 gle of cast 105°, of shell about 115°. This species has two parallel 

 flattened areas on the lateral surface like the intrepid a and cyclas; 

 but its form, the absence of vertical striae from the anterior muscular 

 impression and other characters distinguish it. — lllawarra. 



Genus Cardinia, (Ag.) — Form of the species below-described, trans- 

 verse, and dorsal margin more or less convex without a salient beak; 

 two strong anterior muscular impressions, and one posterior less distinct, 

 the smaller anterior linear, and situated vertically on the front ; the pal- 

 leal impression entire, and not quite reaching to the anterior muscular 

 impression. No cardinal area to the shell, but a strongly defined one 

 to the cast of the interior. The species differ from Cardinia in having 

 the lateral surface posteriorly marked with radiations; the front of an 

 interior cast is strongly truncate, and the flat truncate surface extends 

 on and separates the anterior margins of the large anterior muscular 

 impressions from the medial line ; the cardinal areas in the cast are very 

 long linear, and but slightly widen posteriorly. We refer the Ortho- 

 nota 1 costata, of Morris, to this genus. 



29. Cardinia recta. — Very inequilateral, narrowing much posteri- 

 orly, length 2J times the breadth, dorsal margin a little convex, inferior 

 straight at middle ; lateral surface not depressed, marked with concentric 

 striae and faint radiations, these radiations producing slight undulations 

 in the lines of growth ; palleal and posterior muscular impressions very 

 faint, both of the anterior strong, a convex linear area adjoining the larger 

 extending upward. Interior cast having a very neat, narrow and quite flat 

 cardinal area, with the dorsal margin prominent ; lower edge of the cast 

 very thin; surface quite smooth with faint radiations.— Length 2 inches; 



height T V* L ; thickness T 2 ^ L ; apical angle 125°. The cast resem- 

 bles much VerneuiPs Solemija primana, pi. xix, fig. 5. — lllawarra. 



30. Cardinia cuneata. — Very inequilateral, length about twice the 

 breadth, diminishing posteriorly, and thinning below ; superior margin 

 arcuate, interior strongly concave just posterior to middle, and lateral 

 surface depressed; palleal impression distinct; anterior and posterior 

 muscular impressions excavate. Cast with cardinal areas concave and 

 separated from lateral surface by a strong carina, very long, extending 

 to posterior margin.— Length of cast if inch; height T 5 rfV L ? thick ' 

 ness ^& L ; apical angle of cast 1 10°.— lllawarra. 



Genus Pvramus, (nov. gen.) — Equivalve, somewhat inequilateral, 

 transverse, elliptical, with the front and posterior margins nearly alike, en- 

 tirely closed ; beak somewhat prominent. Ligament external. Palleal 

 impression entire, distant from the margin. Three muscular impressions 

 to each valve, two anterior and one posterior; the larger anterior, sub- 

 orbicular, smaller anterior, facing the same way with the larger, and 

 situated just above its upper angle ; posterior faint. Surface marked 

 with concentric lines of growth. Cast of summit of beak a slender 

 point. Shape nearly of Donacilla and Sanguinolaria, but it differs in 

 its entire palleai impression, and has also two anterior muscular infl- 



