HYRTA 1 21 5 



which coalesce below ; this sculpture is continued about half 

 way over the disk and beyond that it is suddenly replaced by 

 rather strong", concentric ridges ; epidermis greenish-brown. 



Length ii8, height 97 mm. 



Guiana. 

 Hyria latialata SowErby, Conch. Icon., XVII, 1869, pi. 11, 



fig. 4. — Simpson, Syn., 1900, p. 869. 



Sowerby gives a fine figure of this species, but no dimensions 

 and does not describe the interior. It is remarkable for being 

 almost regularly triangular and for having rather fine, subradial 

 sculpture on the earlier growth, which suddenly changes to con- 

 centric sculpture. 



HyRI \ TRANSVERSA Hupe. 



Shell subrhomboid, solid, subinflated, somewhat inequilat- 

 eral; beaks rather full, having a few, very wide, subradial 

 ridges, which extend only a short distance over the disk; pos- 

 terior ridge double, ending in a wide biangulation below the 

 median line; anterior end somewhat narrowed, rounded, with 

 only a feeble wing above ; post-dorsal wing only moderately 

 high, obliquely truncate behind ; surface rather smooth ; epider- 

 mis brownish-black ; hinge strong": teeth somewhat solid ; nacre 

 rose-tinted. 



Length 100, height 60; diam. 35 mm. 



Brazil. 

 Hyria transversa Hupe. Moll. Nouv.. III. 1857, p. 79, pi. xv^ 



fig. I. — SowERBY, Conch. Icon., XVII, 1869, pi. iv, fig. 7. — 



Simpson, Syn.. 1900, p. 860. 



An elongated, subrhomboid form remarkable for its fine, 

 wide, short, subradial bars at and below the beaks. 



Subgenus Triouetrana Simpson, 1900. 



Triqnetrana Simpson, Syn., 1900. p. 869. 



Shell compressed, with a feebly developed posterior wing ; 

 thickened in front ; each valve with about three, somewhat 

 divergent pseudocardinals, which are sometimes nearly smooth 

 and at others break into denticles ; one granular lateral in the 



