72 CRETACEOUS LAMELLIBRANCHIA. 
ribs slender, faintly marked, sometimes indistinct in part, better marked near the 
umbones and on the postero-dorsal region than elsewhere. Anterior teeth (about 
five) short and nearly perpendicular; posterior (about six) more oblique, the 
external being nearly horizontal. Margins entire. 
Measurements : 
(1) (2) (3) 
Length . 5:5 : ; 4°25 : ; 3:70. mm, 
Height g 6-0 a : Ae 5 ; : Are 
Affinities.—This appears to be similar to the form described as Pectunculus 
insculptus, Reuss, from the Priesen Beds of Bohemia, but since the figures’ of 
that form show casts only it is difficult to determine its affinities. The hinge-line 
in P. insculptus seems to be much more curved, forming a fairly sharp angle at 
the umbo, and the teeth are also more numerous than in L. albiensis. 
In P. reticulatus, Reuss,’ the radial ribs are much better marked than in 
L. albiensis. 
Types.—In the Museum of Practical Geology. 
Distribution.—Lower Gault (zones ii, 11, and vu) of Folkestone. 
Limoprsis, sp. Plate XV, figs. 5a—c, 6a—c. 
1897. Lraopsis, sp., H. Woods. Quart. Journ. Geol. Soc., vol. li, p. 379, pl. 
xxvii, figs. 7, 8. 
Description.—Shell small, oval, convex, a little oblique, higher than long; 
margins of valves not crenulate. Casts show fine radial striae, sometimes crossed 
by a few shallow concentric furrows. 
Measurements : 
Length . , : j : : : 8S mm. 
Height. : : ; ; : 
Remarks.—At present this species is known only from internal casts, so that 
“I 
99 
a complete description cannot be given; it seems, however, to be distinet from 
other forms.’ I have not been able to make out satisfactorily the hinge 
1 Geinitz, ‘Char. der Schicht. u. Petref. d. sachs.-bobm. Kreidegeb.,’ pt. 11 (1842), p. 78, pl. xx, 
fig. 17; Reuss, ‘Die Verstein. der bohm. Kreidef.,’ pt. ii (1846), p. 8, pl. xxxv, fig. 5; Fritsch, ‘Stud. 
im gebiete der bohm. Kreidef.,’ v. Priesener Schichten (1893), p. 98, fig. 106. 
2 Reuss, ibid., p. 8, pl. xxxv, figs. 7, 8. 
$ Compare with the following, most of which are known as casts only : 
(i) LZ. calvus, Sowerby, ‘Trans. Geol. Soc.,’ ser. 2, vol. ii (1832), p. 417, pl. xxxviii, fig. 2; 
Zittel, ‘‘ Die Bivalv. der Gosaugeb.,’’ ‘ Denkschr. d. k. Ak. d. Wissensch. Wien. Math.-nat. Cl.,’ vol. 
xxiv (1865), p. 165, pl. ix, fig. 8. 
(i) L. rhomboidalis, Alth, ‘Haidinger’s Naturwiss. Abhandl.,’ vol. ii, pt. 2 (1850), p. 238, 
pl. xu, fig. 17; Favre, ‘ Moll. Foss. Craie de Lemberg’ (1869), p. 121, pl. xii, figs. 11, 12. 
