Fossils from Australia. 157 



pressions which belong together, to each valve, as in Corbis. From 

 the impression of the hinge of a left valve, there appear to be no prom- 

 inent teeth ; it has a very oblique shallow sulcus, directed posteriorly 

 from the centre of the hinge, and a slight excavation anterior to the 

 centre. The form is more transverse and the teeth less distinct 

 than in Corbis. It has not the long lunate muscular impression of 

 Lucina. 



31. Pyramus elliplicus. — Oblong, length half greater than breadth, 

 lower margin arcuate, sides evenly convex, surface strongly but un- 

 evenly marked with regular concentric strice, posterior and large ante- 

 rior muscular impressions rather indistinct, not excavate ; palleal im- 

 pression perceptible and posteriorly plicatulate. Cast of beak acute at 

 a pe*-— Length If inch ; height y 7 ^ L ; thickness T V<j L ; apical angle 

 137 . Another specimen, probably same species, three inches long. 

 Harper's Hill. / P 8 



32. Pyramus myiformis* — Oblong, length two-thirds greater than 

 breadth ; exterior smooth, with faint strife of growth ; lower margin 

 nearly straight, lateral surface below somewhat flattened ; muscular im- 

 pressions distinct, posterior not excavate, large anterior a little so above, 

 smaller anterior deeply excavate, and the surface of attachment facing 

 the same way with the larger; palleal impression faint. Cast having 

 jhe beak terminate in a minute cylinder, and having the lateral sur- 

 face, from the summit obliquely downward and backward, depressed. 

 --Length 2 inches ; height T V(j L ; thickness about T 3 <y 5 <y L ; apical an- 

 gle 148° or 150 a . The front and posterior margin are more broadly 

 rounded than in the preceding, the lower margin straiter, the apical an- 

 gle much larger.— lllawarra. 



33. Nucula abrupta. — Thick, elongate, transverse, rather abruptly 

 arrowing behind the summit, and diminishing posteriorly; posterior 

 °rsal margin much concave ; anterior margin rounded ; cast strongly 



marinate from the beak to the posterior angle, and having a wide and 

 "at cardinal area; palleal impression distinct, somewhat excavate, 

 smooth; anterior muscular impression somewhat excavate, smooth; 

 posterior strongly excavate in the upper part, (in the cast it lies around 

 fte posterior carina, and the upper extremity forms an abrupt angle on 

 the outline of the carina;) surface of cast smooth, some faint radia- 

 ns hardly distinguishable.— Length l£ inch; height $fa L ; thick- 

 ness tVo or ^ L^ apical angle about 135° ; height in the line of the 

 u PPer part of posterior muscle, about half greatest height.— lllawarra. 



34. Nucula ? Harper's Hill. 



3d. CypHcardia rugulosa.— Oblong transverse, anterior part one- 

 h*rd whole length, narrowing rather abruptly from the beak posterior- 

 ly' Posterior surface (flank) broad and flat truncate, with a cannate 

 mar gin extending from the beak to the lower posterior angle ; cardinal 

 a y* distinct, profound ; lateral surface marked with longitudinal stnee 

 ?' growth, which are quite irregular or undulate, making a right angle 

 ^d in some parts a less angle) at the carina ; also a few large obso- 

 lescent longitudinal folds.— Length 2-9 inches ; height ffo L ; thick- 

 ^L; apical angle 132°.— lllawarra. . 



36. CypHcardia sinuosa.- Oblong transverse, anterior part about f 

 * h °le length ; posterior rather rapidly narrowing but not abruptly ; 



