196 CRETACEOUS LAMELLIBRANCHIA. 
Non 1842. Precren putcuenyius, P. Matheron. Cat. Foss. du Bouches-du-Rhéne, 
p. 186, pl. xxx, figs. 4—6. 
== 1 Weysy33, — — L. Reeve. Conch. Iconica, vol. viii, pl. xxxii, fig. 142. 
1872 -- — H. B. Geinitz. Das Elbthalgeb. in Sachsen (Palaon- 
tographica, vol. xx, pt. 2), p. 33, 
pl. x, figs. 2—4. 
— 1877. a _ A. Fritsch. Stud. im Gebiete der bohm. Kreide- 
format.: II, Die Weissenberg. u. 
Malnitz. Schicht., p. 136, fig. 130. 
— 1893. -— — R. Michael. Zeitschr. d. deutsch. geol. Gesellsch., 
vol. xlv, p. 243. 
Deseription.—Shell small, oval, rounded, height equal to, or shghtly greater 
than the length; nearly equilateral, the postero-dorsal margin a little longer than 
the antero-dorsal. Convexity of valves small. Apical angle about 103°. Ears of 
moderate size, unequal. 
Right valve with a variable number (twenty-three to forty-four at the margin) 
of broad, flattened, radial ribs, separated by much narrower, shallow grooves ; in 
approaching the umbo some of the ribs become united in pairs. Near the anterior 
and posterior borders ribs are small or absent. Both ribs and grooves are marked 
by numerous fine radial strize, which, in the middle of the valve, are parallel with 
the ribs, but cut them more and more obliquely in passing toward the anterior and 
posterior margins, which they meet at acute angles. Anterior ear longer than 
high, with the outer margin rounded and a rather small sinus; posterior ear 
smaller, triangular, higher than long, outer angle obtuse; both ears with radial 
strie lke those on the valve, and the anterior ear sometimes with a few concentric 
ridges also. 
Left valve with narrow, elevated, sharply-limited ribs, some of which (often 
alternate ones) do not reach the neighbourhood of the umbo. Ribs small or absent 
near the anterior and posterior margins. Grooves between the ribs broad and 
deep, marked by radial striz like those on the right valve. Summits of ribs 
slightly serrate. Ears triangular, the posterior a little smaller than the anterior 
and with the outer angle obtuse; both ears with radial strie. 
Measurements : 
(1) (2) (3) (4) 
Length : 20°5 : 15:0 : 12°5 ‘ 10°5 mm. 
Height ; 20°5 : 16:0 : 13-0 : GIO aes 
(1—4) from Trimingham. 
Afjinities.—P. lineatus, Nilsson, is a left valve of P. pulchellus. P. spurius, 
Goldfuss, from Haldem, of which the type is in the Munich Museum, has been 
shown by Hennig to be identical with P. pulchellus. The form from the Planer- 
kalk of Strehlen referred by Geinitz to P. pulchellus is regarded by Schliiter, 
