71 
Eurydesma cordatum, Morris. 
(PI. XVII ; PI. XVIII, Fig. I ; PI. XIX, Figs. 3-5 ; PI. XX, Figs. 2-6 ; PI. XXI, Fig. 1 ; 
PI. XXII, Figs. 3-5; PI. XXIII, Figs. l-I; PI. XXV, Fig. 3. ; PI. XXVI, Fig 4.) 
Isocardia (?), j- de C. Sby., Mitchell’s Three Exped. Int. E. Austr., 1838, I, PI. ii, figs. 1-2. 
Eurydosmn cordatct, Morris, Strzelecki’s Phys. Descr. X. S. Wales, &c., 1845, p. 276, 
PI. xii. 
Eurydesma elliptica, Dana, Am. Joum. Sci., 1847, IV (2), p. 158. 
„ globosa, Dana, Ibid., p. 158. 
„ cordata, Dana, Wilkes’ U.S. Expl. Exped., X (Geol.), 1849, p. 700, Atlas, 
PI. viii, figs. 1, la. 
,, elliptica^ Dana, Ibid., p. 700, PI. vii, figs. 6, a-d. 
,, globosa, Dana, Ibid., p. 700, PI. vii, figs. 7 and 7ra. 
j, aacculiis. Dana, Ibid., p. 700, PI. vii, figs. 8a-e (non Pachydomus sacculus, 
McCoy). 
,, cordata, Johnston, Syst. Acc. Geol. Tas., 1885, PI. xviii., fig. 16, PI. xix, 
figs. 1, la. 
EachydomuS globosus, Johnston, Ibid., PI. xviii, figs. 1, la. 
(?) ,, Eonincki, Johnston, Ibid., PI. xviii, fig. 3. 
Eurydesma cordata, Eth. fil., Geol. Pal. Q’land, Ac., 1892, p. 278. 
(?) Myaliua {^Leiomyalind) antarctica, Freeh, Abhandl. Geol. Specialkarte Preuss. 
Thiiring. Staaten, 1891, IX, Heft 3, 
p. 201, figs. 21-23. 
Specific Characters. — Shell obliquely cordate, 'valves highly ventricose 
in umbonal region, always produced antero-ventrally to a greater or less 
extent, sometimes more anteriorly than ventrally, frequently flattened 
towards the posterior and ventral margins. Test greatly thickened in the 
umhonal regions ; an ill-defined, oblique cincture sometimes present, 
extending from the postero- ventral margin upwards for about half the height 
of the shell. Umhones much incurved and overhanging the lunule ; umbonal 
slopes rounded and steeji, more particularly the anterior; lunule widely 
cordate, and deeply excavate. Articulus very massive; resilifer arcuate 
and tapering posteriorly ; cardinal folds and retractor scars as described on 
pp. 65 and 59. Sculpture concentric, the surface rugged and interlineate, 
and at times radiate. 
F 
