New and Rare Fossils. 49 



Fain. CYTHERELLIDAE. 



Genus CYTHEKELLA. Jones. 



Cytiikhklla AURicuLUS, sp. nov. (Plate IX., Figs. 4:2a, h ; 43). 



Description. — Cai-apace oblong, eonipiessed. Seen from the 

 side, valves subquadrate, with a marginal raised rim and depressed 

 central area relieved in the median line by a raised longitudinal 

 and crescentic bar. In the young example figured the central 

 raised band starts from the dorsal margin, and continues to curve 

 down and round, all but enclosing a central suboval space; dorsal 

 margin neaily straight, with a median concavity, ventral broadly 

 concave: ijoth extremities widely rounded. Edge view narrow 

 oblong, relieved l)y the marginal and median prominences. The 

 genei-al, depressed surface of the valve is roughly granulate, the 

 marginal and central bars smooth. 



Dinntxioiis. — Length of lai'ger type specimen. .71 mm.; width,. 

 .41 iiiiii. ; thickness of carapace. .'■') mm. 



Length of smaller type specimen, .5 nnn. ; width, .27 mm. 



Affinities. — There is one living species, Cytherella latimnrginata, 

 G. S. Brady, 1 which resembles the above in having an encircling 

 fillet around the margin, but the centre of the valve is occupied by 

 a long, rounded protuberance, instead of a narrow curved bar as 

 in C. auriculus, the latter more nearly reseml)ling the contour of an 

 ear, hence the name. 



The closest affinity lies, however, with some Cretaceous forms 

 well known from the English and European Chalk, the central type 

 of which is Ci/tlierella n'iUiamsoiiiaiKi . Jones. 2 This species has the 

 central bar broken to some extent, whilst the restricted character 

 of the central ornament, especially in our smaller figured type, is 

 perhaps more nearly approached in V ijthereUa chapmani, Jones, 5 

 from the Gault of Godstone, Surrey, England. 



It is extremely curious to find this species and the previously 

 mentioned Cytheropteron postiunbo/iaf inn of the Austi-alian Miocene 

 so closely approaching their Cretaceous analogues. 



Occurrence. — Bore 11, 219-260 feet (Kalimnan). 



1. Rep. Chall. Zool., vol. i., pt. iii., 1880, p. 178, pi. xxxvi., fi<rs. 7«-<?. 



■2. Mon. Cret. Entom.(Pal. Soc), 1849, p. 31, pi. vii., fij;-;. -^tki-h. Id., ibi<l., ISltO, p. 48, pi. iii., 



figs. r.r..62. 



3. Mom. Cret. Entoni. (Pal. .Soc), 1890, p. 49, pi. iii., fi^-. 70. 



5 



