New and Rare Fossils. 309 



^examples, with the distinction, however, that the denticulatious 

 on the inner vential border in (J. conctntrica are wanting in 

 Verco's Bpecies. 



Distrihutwn.—BoYQ 8, 204-210 feet. Bore 9. 263-273 feet. 

 Bore 11, 175-197 feet; 197-199 feet. 



Fam. CONDYLOCARDIIDAE. 

 Genus CONDYLOCARDIA. Bernard. 



■CONDVLOCARDIA TKNUICOSI'AK, Sp. HOV. (Pi. XXVll., FigS. \1 ll-C ;. 



Description. — Shell very small, shining, of a cream colour. 

 •Ovate wedge-shaped, inequilateral; inflated at the umbonal region 

 and depressed towards the ventral. Dorsal margin straight; an- 

 terior end tapering and bluntly rounded at the ventral angle; 

 posterior end short and widely rounded towards the ventral. 

 Interior of shell smooth, with feeble muscular impressions; ven- 

 tral edge on the commissure bearing a series of minute depressions 

 and elevations, passing into thin, diminishing riblets within. 



External surface sculpture consisting of about 36 narrow, de- 

 pressed or sub-acute riblets, slightly varying in strength and dying 

 out before reaching the umbonal area; crossed at irregular inter- 

 vals by several w^ell-marked concentric growth-lines. 



Cardinal border, short, straight, Left valve with a strong bifid, 

 imedian cardinal tooth, and feeble anterior and posterior lateral 

 ■teeth; right valve with a triangular anterior cardinal, behind 

 •which is a deep fossa for the median cardinal of the left valve. 



Prodissoconch smooth, subovate, slightly salient post-ventrally ; 

 •umbonal aspect depressed. 



Dimensions. — Holotype (left valve) from Bore 10. 310-320 feet. 

 Length, 2.15 mm.; height, 1.77 mm. 



Observations. — This species is a very distinct form. It shows 

 .some relationship to Condylocardia pectinata, Tate and May sp.i 

 in its general form and hingement, but in that species the orna- 

 ment is a coarse radial ribbing instead of fine costulations, as in C 

 tenuicostae. 



Distribution.— Bore 8, 225-226 feet. Bore 10, 186-190 feet; 225- 

 230 feet (paratype); 310-320 feet (holotype). Bore 11. 175-197 

 feet; 197-199 feet. 



1. Carditella pectinata, Tate and May, Trans. Roy. Soc. S. Austr., vol. xxiv., 1900, p. 103. 

 Proc. Linn. Soc. N. S. Wales, vol. xxvi., 1901, p. 435, pi. xxvii., fij^. 96, 97. See also Hedley, Ree. 

 Austr. Mus., vol. vii., No. 2, 1908, pi. xxv., figs. 43-45. 



8a 



