OF THE ANTWERP CRAG. 407 
P. ensiforme occurs living in the British Seas and in the Levant, and has been found 
in many of the Post-tertiary deposits of England, Scotland, Wales, and Ireland. 
One or two valves only occurred, in the Sables moyens (zone & Bryozoaires). 
Fam. CYTHERELLID. 
Genus CYTHERELLA, Bosquet. 
Valves elongated, flattened, thick and hard, very unequal; the right much larger 
than the left, and overlapping throughout the whole circumference, presenting round 
the entire inner margin a distinct groove, into which the valve of the opposite side is 
received. 
CYTHERELLA PARALLELA (Reuss). (Plate LXII. figs. 2 a-2 ¢.) 
Cytherina parallela, Reuss, ‘ Foram. u. Entom. Kreidemergels y. Lemberg,’ Haidinger’s Abhandl. 
vol. iv. p. 47, pl. vi. fig. 1 (1850). 
? Cytherella pulchra, Brady, Trans. Zool. Soc. Lond. vol. v. p. 361, pl. lvii. figs. 1 a-d (1865). 
Carapace, as seen from the side, oblong elliptical, nearly equal in height throughout, 
height equal to about half the length; extremities rounded; dorsal margin nearly 
straight, ventral sinuated in the middle. Seen from above, compressed, ovate, width 
equal to one third of the length. End view ovate. Surface perfectly smooth. Length 
gg inch (0°85 millim.). 
This species occurred sparingly in both beds of the Sables inférieurs and in the zone 
a Bryozoaires of the Sables moyens. 
CYTHERELLA ELLIPTICA, nov. sp. (Plate LXII. figs. 6a, 6.) 
Valves, as seen from the side, elliptical, width equal to two thirds of the length; 
extremities rounded; dorsal margin nearly straight, ventral convex. Seen from above, 
ovate, widest behind. Surface smooth, with distant round impressed puncta. Length 
go ch (0°85 millim.). 
One valve only of this species was found, in the Panopea-bed of Kiel. It seems to 
be distinct, but very nearly approaches C. beyrichi as figured by Speyer and Bornemann. 
It is not, however, the C. beyrichi of other authors, a form which is in all probability 
identical with C. abyssorum of G. O. Sars, and is so considered by that author. 
CYTHERELLA NODOSA, nov. sp. (Plate LXII. figs. 5 a—5 d.) 
? Cythere varians, Bornemann, Zeitschr. d. deutsch. geol. Ges. 1855, p. 365, pl. xxi. figs. 4, 5. 
Carapace, as seen from the side, elliptical, higher in front than behind, height equal 
to two thirds of the length; extremities rounded; dorsal margin well arched, ventral 
nearly straight; the anterior margin raised into a distinct rounded lip; and near the 
