78 



with the former than the latter. But L. anomala is suborbicular 

 in shape, with a nearly straight dorsal line, whilst my species is 

 triangularly oval or somewhat axiniform in marginal outline, and 

 has a strong tessellated ornamentation. The Syrian Cretaceous 

 species, L. percancellata, Whitfield, Bull. Mus. Nat. Hist., iii, p. 

 403, t.b, f.b, 1891, has a somewhat similar cancellate ornament, 

 but that fossil is nearly circular in outline. 



Until the interior is known, the generic location of 

 L. Bonythoni will remain uncertain, though the shape and orna- 

 mentation are not incompatible with a reference to Lucina, but, 

 on the other hand, the transverse direction of the umbonal 

 incurvature may imply other affinities, if other than a mere 

 specific characteristic. 



The distinguishing features of L. Bonythoni are : — The axial 

 direction of the umbo, the axiniform shape, the cancellate 

 surface-ornamentation (particularly the frilled edge of the con- 

 centric growth-lines). 



Flatopis (?) eoppugata, sp. nov. (1898). 



The fossil under observation is not like any figured species 

 belonging to the Cretaceous fauna of Australia, though it has 

 some resemblance to certain species of so-called Cytherea, but yet 

 is more Astarte-MkQ than they are. The interior is unknown, and, 

 therefore, the generic relations are extremely dubious. Never- 

 theless, one exterior feature will narrow the arena of comparison, 

 that is the possession of an erect exsert ligamental plate to each 

 valve, as in Psammobia and other Tellinids, and thus indicates an 

 external ligament. Among the genera presenting this character, 

 Flatopis, Whitfield, Bull, Mus. Nat. Hist., iii., p. 399, 1891, 

 seems to include the main external features presented by the 

 Australian shell. Flatopis, which is placed by its describer in 

 Astartidse, contains species which "externally somewhat resemble 

 shells of the genus Astarte,'' the hinge dentition differs from Opis 

 and Opiosma ; they have a "flattened or depressed convex form," 

 and "possess an abruptly flattened, or even depressed slope, 

 which in many is sharply flattened, or even depressed between 

 the umbonal angles, and the very ill-defined, although large- 

 sized, lunule." 



Shell transversely triangular, somewhat cuneiform, convexedly 

 depressed. Umbones large, obtuse, antemedian; lunule ill- 

 defined. The dorsal slopes straight, inclined at an angle of 95°, 

 the posterior considerably the longer ; post-ventral extremity 

 roundly-pointed (the shell is deficient in this region), the ventral 

 margin nearly straight to beyond the middle line, thence curving 

 rapidly upwards to form the well-rounded anterior extremity. 

 The post-dorsal line is bounded by a narrow declinous lanceolate 



