cragin.] DESCRIPTIONS OF SPECIES. 65 
shell is shown. The triangular-ovate to quinquelateral outline pre- 
sents dorsally a nearly straight incline back of the beaks and is 
strongly excavated in front of them; has a long, gently convex base, 
and is posteriorly or infero-posteriorly truncate, and narrowly 
rounded anteriorly. The shell is quite strongly compressed, and the 
ribs of either valve reach 11 in number. The ribs are coarse, strongly 
elevated, gently compressed, and separated by round-bottomed inter- 
vals a little wider than themselves. Of more than GO specimens 
collected from east of Malone, a single one, among the young exam- 
ples, is quite ventricose, gapes slightly in the interval between two of 
the subdistal ribs, and exposes there a double and interlocking set of 
strong denticles like those of the internal margins of the adult shell. 
Measurements. — The specimen figured has the following dimen- 
sions: Height, 10 mm.; length, 14 mm.; breadth, 4 mm. In less 
perfect examples a height of 12 mm. and a length of 1G mm. are indi- 
cated. 
Astarte malonensis Cragin. 
PI. XI, figs. 10, 11; PI. XII, figs. 1-3. 
Venus malonensis Cragin, 18D3, Fourth Ann. Rept. Geol. Survey Texas, pt. 
2, p. 210, PI. XXXV, figs. 1 and 2 ; and Jour. Geol., vol. 5, p. 817. 
Shell rather large, thick-valved, moderately ventricose, or some- 
imes slightly compressed, inequilateral, broadly and variably sub- 
)vate; the dorsal side flattish-convex behind the beaks and excavated 
n advance of them; the anterior side rounded or slightly subtruncate 
rom being a little prominent in its upper part; the posterior side 
•ather narrowly convex; the base broadly convex; beaks only moder- 
tely elevated, approximate, their summits varying from subcentral 
o a position just back of the anterior third; lunule and escutcheon 
leeply and abruptly impressed, especially the former, which is nar- 
ow-cordate; cardinal teeth 2-2, unstriated, the central of the right 
alve being much larger than the anterior and the posterior of the 
ft valve being larger than the central;" a posterior remote, hori- 
ontal, pliciform lateral tooth in either valve fitting into a corre- 
onding groove in the other; pallial line sinuate, its impress on (lie 
est-preserved casts crossed by faint radial plications; pallial sinus 
mple, its anterior and posterior limbs, respectively, subvertical and 
ubhorizontal (the latter a little ascending), its fundus obtuse; valve 
largins crenulated within; shell ornamented with numerous subequal 
p unequal concentric, coarsely linear pliciform growth lines, whose 
squence is usually interrupted by remote and more elevated folds, 
"The cardinal teeth are here regarded as 3 in each valve, but with 1 in each valve 
)Solete. 
Bull. 200—05 m 5 
