FOSSILS OF NEW SOUTH WALES. 703 
a projection in front of the beaks. Posterior muscular impression faint——Length 14 
inches, height much less than half the length.—Plate 8, fig. 8 a, 6, views of a cast, natu- 
ral size. 
Harper’s Hill. 
The texture of the valves is fibrous as in the imbricata, and the form of the species is 
in general similar, though thicker and less oblong, with the cardinal margin much 
shorter. It resembles in shape an Arca. The large muscular impression stands up, 
nearly as in Bronn’s genus Myophoria, (Lethzea Geogn. pl. 11, fig. 6.) 
The surface of the cast shows some faint traces of radiations towards its anterior por- 
tion. The height of the shell was probably about two-thirds its length. 
Modholopsis arcodes, Exped. Foss., Amer. Jour. Sci., ii. Ser., iv. 159. 
Norr.—Fig. 9, plate 8, represents a part of a cast of an allied species, probably a 
young individual. 
58. Cypricarpia pR&#RuPTA (Dana).—Moderately thick ; elongate; broader behind 
and orbiculate ; in front abruptly truncate, with a vertical fold quite near the front margin, 
and another excavate area obliquely downward from the beak. Surface smooth, with 
some fine strice of growth, and very faint radiations ; convex posteriorly, without a carina. 
Cardinal margin straight, and gradually rounding into the posterior margin; inferior 
margin excavate posterior to middle. Anterior muscular impression strong, nearly cir- 
cular, situated close to the front margin; posterior indistinct—Length 1 z‘5 inches ; 
greatest height #,3, L.; apical angle 100°.—Plate 8, figure 10, natural size. 
District of Illawarra. 
This species closely resembles the Modiolopsis faba of Hall (New York Palzont., pl. 
35, fig. 6), which is a lower Silurian species. The breadth in front is about three-fourths 
the greatest breadth. 
Modiolopsis prerupta, Exped. Foss., Amer. Jour. Sci., il. Ser., iv. 159. 
59. Cypricarpra siriqua (Dana).—Rather thin, oblong, broader posteriorly, and mar- 
gin orbiculate ; front a little projecting, and rounded below. Cardinal and inferior margins 
straight, and rounding into the posterior, Sides convex, not carinate behind, compressed 
below the beak. Anterior muscular impression distinct, situated near the front margin. 
Surface concentrically subplicate—Length 17 inches; greatest height 52, L.; apical 
angle about 130°.—Plate 9, figures 1 a, 0, different views, natural size. 
District of Illawarra. 
This small species resembles the Mytilus (Modiola) Teplofi of Verneuil (Russia, pl. 
19, fig. 17) ; but it is somewhat higher proportionally, has the front a little more project- 
ing, and the posterior margin is more nearly semicircular. Still it is possible that they 
are identical. Verneuil’s species is from the coal mines of Lissitchia in Russia, 
Modiolopsis siqua, Exped. Foss., Amer. Jour. Sci., 11, Ser., iv. 159. 
60. Cypricarpta stmpLex (Dana).—Moderately thick ; elongate ; oblong sub-ellipti- 
cal, (length more than twice the height,) rather broader posteriorly, and elliptically 
rounded behind. Front margin obliquely truncate and rounded below. Cardinal margin 
scarcely arcuate, rounding into the posterior, Inferior margin regularly arcuate. Late- 
