APPENDIX. 353 
t. 19, f.19. Bluntly and rather obliquely subquadrate, extremely 
inequilateral, thin, ventricose, white under a very thin olive skin, 
smooth, subarcuated ventrally. Front extremity broadly rounded, 
its dorsal edge scarcely sloping; extremity of the excessively short 
hinder side obtuse in the middle, towards which a faintly depressed 
line runs from the small and incurved beaks. Umbones much 
swollen: no marked umbonal ridge. Ligament elongated, not 
sunken: inside bluish white. 13. Senegal. In each valve is a 
transverse laminar lunular tooth, and a very slender cardinal one ; 
a compound sublaminar tooth intervenes in the right valve. 
Cyrenoipa Cuminer (t. 15, f. 5). Broadly suboval, subinequi- 
lateral, thin, swollen, white under a slight dirty yellow epidermis, 
smooth, with a faint umbonal ridge; ventral edge arcuated, ascending 
evenly at each extremity; front extremity bluntly (not broadly) sub- 
biangulated, its dorsal edge hardly sloping ; hinder extremity rounded, 
its dorsal edge scarcely, if at all, incurved: umbones moderately pro- 
minent; beaks very small, incurved; neither lunule nor lozenge ; 
ligament short, narrow, not projecting: inside white: a deeply 
cloven and a small simple cardinal tooth in each valve. }4. 
Philippines. 
CYRENOIDA OBLONGA (t. 15, f. 6). Transverse, subquadrate-oboval, 
inequilateral, thinnish, more or less ventricose (especially in front), 
both within and without glossy white, partially covered with a slight 
epidermis of a canary-yellow, smooth, arcuated at the ventral margin ; 
front side rather the shorter, evenly rounded; hinder side bluntly 
angular above, rounded below, its dorsal edge almost horizontal; um- 
bones little promiment; beaks inclined: no lunule; ligament short, 
small, narrow, seated in an elongated narrow shelving area, whose 
sides are sharp at the edge; teeth as in C. Cumingii. 1%.  Philip- 
pines. The surface is retuse between the area and the site of an 
umbonal ridge. 
On Gatatuea (p. 99). Dunker has published a G. Bengoensis, 
and Philippi G, leta, rubicunda and tenuicula in the Zeit. Mal. 1848, 
1849. 
On Cyprina (p. 95). C. triangularis and minima (p. 95) are iden- 
tical; they are not true Cypring, but Cytheree of the Circe group. 
The Venus pumila of Lamarck (== Cyt. Cyrilli, Scacchi) is only a 
varietal form. 
On CyrHerea (p. 95). C. pellucida (p. 101) is figured in Sow. Th. 
2, t. 136, f. 190, and C. wnbonella (p. 102) at t. 180, f. 64, 66 of the 
same work. Should the C. cyynus of Sowerby be identical with ours 
(p. 109), the Mediterranean locality is, to say the least, uncertain. 
For additional species consult the monographs by Sowerby (Th. Con.), 
and Deshayes (British Museum Catalogue). Examine, hkewise, 
25 
