Fossils from Australia. 155 



Tialf a line thick. Although we have not yet made out the teeth of 

 the hinge, we propose to describe the species under the generic name 

 Astartila. 



23. Astartila intrepida. — Thick, somewhat transverse, neatly but 

 somewhat unevenly concentric striate ; anterior part about ^ the whole 

 length. Anterior muscular impression excavate ; smaller subquadrate 

 or a iittle oblong ; larger marked with a number of fine vertical strise 

 on the lower posterior quarter; antero-lateral surface of the interior 

 with two parallel flattened areas, the one adjoining the muscular im- 

 pression convex, (concave in the cast.) — Length If inch ; height -^ L ; 

 thickness T %^ L; apical angle about 120°. — Illawarra. 



24. Astartila cyprina. — Thick, transverse, length more than one 

 third greater than height; palleal impression very distinct, inner sur- 

 face of valve very minutely rugose, below palleal impression radiately 

 subplicate ; posterior muscular impression not excavate, crossed verti- 

 cally by a fold ; large anterior deeply excavate, convex, crossed by a 

 few faint vertical lines, which are closer towards the posterior margin ; 

 smaller somewhat excavate, oblong sigmoid. Cast with antero-lateral 

 surface simply a little flattened. — Length 2 T V inches ; height ^ L ; 

 thickness T ^% L ; apical angle about 118°.— Illawarra. 



25. Astartila cytherea.— Thick, slightly longer than the height; in- 

 ner surface smooth, palleal impression rather faint; posterior muscular 

 impression large and very distinct, very slightly excavated, not inter- 

 sected by a vertical fold ; larger of the two anterior deeply excavate, 

 the excavation deep and very abrupt on the upper side, four or five 

 stria? crossing the muscular impression vertically near posterior margin ; 

 smaller anterior oblong sigmoid, but not excavate. Cast with antero- 

 lateral surface simply somewhat flattened. — Length of cast 1£ inch ; 

 hei S ht tA L ; thickness T ^ L ; apical angle 1 12°.— Illawarra. 



26. Astartila polita.—RaXher thin, somewhat transverse ; surface 

 smooth and shining, with faint lines of growth ; muscular impressions 

 scarcely excavate and palleal impression faint; the larger anterior very 

 even and without vertical strise or plications ; a slight fold in the sur- 

 face just anterior to posterior muscular impression, and a smaller one 

 crossing this muscular impression. Cast with antero-lateral surface 



simply very slightly flattened.— Length 1 to If inch ; height ^ L ; 

 thickness jfr L ; apical angle about 1 13°.— Illawarra. 



2~- Astartila cyclas.-Raihev thin, slightly transverse ; surface mark- 

 ed unevenly with concentric striae ; posterior muscular impression very 

 distinct but hardly excavate, a fold in the inner surface of the valve just 

 anterior to it ; both of the anterior muscular impresses str ongly exca. 

 vate ; the larger without vertical stride ; the smaller placed oWi<J»ely so 

 that the cast of it is a linear trenchant ridge ; palleal ™9*«%» very 

 distinct, somewhat plicatulate. Cast with summits of beaks quite . 

 *e lateral surface strongly flattened, and another finite ned I area adjom 

 ln g anterior muscular impression—Length 1* mch ; he.g Jit , ^ b , 

 thickness ^L; thickness of cast jfrU apical angle ISo 



"lawarra u *w A 



28. Astartila inmseersn.-Thick, transverse, length fuHa third 

 f eater than height; posterior muscular impression faint > cr °^ v 



to W vertically, and another more distinct in the surface just anterior to 





