DIPLODON 1297 



concentricalh sulcate striate ; pseudocardinals conical ; laterals 

 elongated, lightly curved ; nacre bluish-white, shining. 



Length 6(), height 41, diani. 25 mm. 



New South Wales. 

 Unto lessoiii Kustkr, Conch. Cab., 1856, p. 135, pi. xxxvi, 



fig- 4- 

 Diplodon Jcssoni Simi\S()N. Syn., 1900, p. 890. 



Unio anstra'is Kustkr, Conch. Cab., 1861, p. 230, pi. lxxvii, 



fig. 6. 



I am not at all sure that this is not D. iial^eaiiciisis. The fig- 

 ures are taken from specimens in which the umbonal region 

 is badly eroded. The shape of the shell, its color and that of 

 the epidermis agree closel}^ with the same characters in napea- 

 nensis, but the pseudocardinals are represented as conical. In 

 the latter species they are compressed or subcompressed in all 

 the specimens I have seen. 



Diplodon aitstr.m.is ("Lamarck," Hanley). 



Shell elliptical, slightly obovate or subrhomboid, thin to sub- 

 solid, convex to inflated, more or less inequilateral ; beaks mod- 

 erately full and elevated, their sculpture not observed ; poste- 

 rior ridge but little elevated, subangular or rounded; there is 

 often a sort of low. wide, radial ridge at some distance in 

 front of the posterior ridge, the base line being full where it 

 ends ; surface with rather strong, irregular, concentric sculp- 

 ture ; epidermis pale olive to dark brownish, scarcely shining; 

 pseudocardinals compressed, one in each valve, with some- 

 times a feeble second one in the right valve ; laterals delicate, 

 remote, often short, single in the right valve, often double in 

 the left : muscle scars shallow ; nacre dull, whitish or bluish, 

 sometimes a little thicker in front. 



Length 62, height 41, diam. 24 mm. 



Length 67, height 42.5, diam. 28 mm. 



Australia ; Tasmania. 

 Unio australis Lamarck, An. sans. Vert., VL 1819, p. 80. — 



Hani.ky, Biv. Shells, 1843, P- 192, ph xxi, fig. 25. — Phil- 



ipp]. Conch., TIL 1848, p. 81, pi. V, fig. 5. 



