Fossils from Australia. 155 
half a line thick. Although we have not yet made out the teeth of 
= nen we propose to describe the species under the generic name 
Sl 
23. Astartila intrepida.—Thick, somewhat me ess ay 
- Astertila ig ete ee transverse, len ate more than one 
smaller somewhat excavate, siamo nein Cast with antero- lateral 
surface es y a little flattened. —Lengt h 2,4 inches; height 74% L; 
—IJllawarra 
25, date cytherea.—Thick, slightly longer than the height; in- 
ner surface smooth, zooenen impression rather faint; posterior muscular 
impression large and very distinct, sk slightly excavated, not inter- 
sected by a vertical fold; larger of the two anterior deeply excavate, 
e 
smaller anterior oblong sigmoid, but not excavate. Cast with antero- 
a Welt simply somewhat flattened. ye th of cast 11 inch; 
heigh oo Li ; thickness ;%8; L; apical angle 112°, Illawarra. 
artila _polata. —Rather thin, somewhat transverse ; surface 
face just anterior to posterior muscular impression, and a smaller one 
crossing this muscular impression. Cast with antero-lateral surface 
simply sae | slightly flattened.—Length 1 to 12 inch; height 7% 
thickness 35°; L; apical angle about 113°.—J//awarra, 
27. Reson iili spell —Rather thin, slightly transverse ; surface mark- 
nevenly with concentric strie ; 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 impressions strongly exca- 
vate; the larger without vertical striae; the smaller placed obliquely so 
that the cast of it is a linear trenchant ridge ; palleal impression very 
distinct, somewhat plicatulate. Cast with summits of beaks quite thin, 
the lateral surface Ke flattened, and another flattened area a ame 
ing anterior muscular impression. oe pare 14 inch; height 49, L 
thickness 435 L; chineaane of cast 34% L; apical angle 1385°.— 
lawarra. 
28. Astartila transversa.—Thick, transverse, length full a third 
greater than height; posterior muscular impression faint; crossed by a 
fold vertically, and another more distinct in the surface just anterior to 
