OF THE ANTWBKP 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 a Bryozoaires). 



Fam. CYTHERELLIDiE. 



Genus Cytheeella, 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. 2a-2c.) 



Cytherina parallela, Reuss, " Foram. u. Entom. Kreidemergels v. Lemberg," Haidinger's Abhandl. 



vol. iv. p. 47, pi. vi. fig. 1 (1850). 

 H Cytherella pulchra, Brady, Trans. Zool. Soc. Lond. vol. v. p. 361, pi. Ivii. figs. \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 siauated in the middle. Seen from above, compressed, ovate, width 

 equal to one third of the length. End view ovate. Surface perfectly smooth. Length 

 ^Q inch (0'85 millim.). 



This species occurred sparingly ia both beds of the Sables inferieurs and in the zone 

 a Bryozoaires of the Sables moyens. 



Cytherella elliptica, nov. sp. (Plate LXIL figs. 6 a, 6 h.) 



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 

 ^0 inch (0'8-5 millim.). 



One valve only of this species was found, in the Pa?iqpcea-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.) 

 1 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 



