700 APPENDIX IL 
49. EurypErsma eniriprica (Dana).—Moderately thick ; elliptical. Exterior surface 
evenly convex with faint concentric lines of growth, (elliptical in form,) and no radiations. 
Inferior margin regularly arcuate.—Length 27 inches; height ;8%, L.; thickness 555 L. 
or °fo H.; apical angle 124°,—Plate 7, figs. 6 a, b, c, d, different views, natural size. 
Harper’s Hill. 
Eurydesma elliptica, Exped. Foss., Amer. Jour. Sci., ii. Ser., iv. 158. 
50. EurypEsma eLoposa (Dana).—Very thick, ventricose; orbicular. Lateral 
surface evenly convex, with faint concentric lines of growth regularly circular, and no 
radiations. Inferior margin regularly arcuate-—Length and height 14 inches; thickness 
veo L.; apical angle 97°.—Plate 7, figs. 7, 7 a, different views, natural size. 
District of Illawarra. 
Eurydesma globosa, Exped. Foss., Amer. Jour. Sci., ii. Ser., iv. 158. 
51. Euryprsma saccutus (M’Coy) Dana.— Very thick, ventricose, length and 
height nearly equal. Lateral surface compressed at middle, and the lines of growth bent 
where leaving this compressed area; also a few distant concentric undulations. Beak 
prominent and rather narrow. Inferior margin straight at middle or a little excavate.— 
Length 37 inches; thickness ;°8, L., or nearly as great as height; apical angle between 
90° and 100°.—Plate 7, figures 8 a, 6, representing an imperfect specimen, natural size; 
c, back view of beak of the left valve and thickened shell below; d, sectional view of the 
valve through the beak and hinge, vertically ; e, inner view of same, showing the interior 
surface, and hinge of left valve. 
Harper’s Hill. 
This species is as much thicker than the globosa, as the globosa is thicker than the 
elliptica. It is also distinguished by its flattened lateral surface and slightly excavate 
lower margin, the direction of the outline of which is indicated by the concentric striz of 
growth, which bend a little downward near the middle with a broad curve. The surface 
does not appear to have been radiated. 
Pachydomus sacculus, M’Coy, Ann. and Mag. Nat. Hist., vol. xx., p. 301, pl. 14, fig. 5. 
52. Eurypesma corpata (Morris.)—Rather thick, ventricose, orbicular. Lateral sur- 
face slightly compressed at middle, marked with concentric lines of growth and low ridges, 
and also with faint radiations. 
Harper’s Hill. : 
This species, described by Morris, was first figured by J. D. Sowerby in Mitchell’s 
Australia. The indistinct radiate striations are stated by Morris to be well represented 
in J. D. Sowerby’s figure. This figure (his figure 1, pl. 2) represents a much thinner 
species than the last, and from either of the preceding it is distinguished by its radiations 
and slightly flattened lateral surface, as well as form, Figure 1, plate 8, represents a species 
allied to this in form, and with faint radiations in the cast and texture of the shell, though 
not well seen in the exterior. The surface is marked with coarse, low, concentric ridges. 
