334 



Area (Barbatia) decussata, Sowerby. 



1833. Byssoarca decussata, Sowerby, Proc. Zool. Soc. p. 18. 



1844. Area decussata, Reeve, Conch. Icon, vol. ii. pi. xii. fig. 81. 



? 1873. Barbatia sinuata, Hutton, Cat. Tert. Moll. N.Z. p. 27. 



1880. Barbatia decussata, Hutton, Man. N.Z. Moll. p. 162. 



1893. Area decussata, Hutton, Linn. Soc. N.S.W., Macleay Mem. Vol. p. 86. 



The shell of this species closely resembles that of B. simulans, 

 but that portion anterior to the umbones is relatively shorter, and 

 the latter are very broad and incurved ; perhaps the most striking 

 differences are the larger number of teeth on the hinge and the 

 greater distance between the umbo and the beginning of the ridge 

 which denotes the commencement of the anterior section of the 

 hinge-line ; the anterior margin is less rounded than in B. simulans, 

 and the ventral margin is usually more deeply sinuated. 



Dimensions. — Height 22 mm. ; length 38 mm. 



Form, and Loc. — Pliocene : Shakespeare Cliif, New Zealand. 



L. 10442. Examples of both valves of the adult. 



Sir James Hector Coll. 



Area (Barbatia) pumila, Tate (sp.). 



1886. Barbatia pumila, Tate, Trans. Roy. Soc. South Aust. vol. viii. p. 142, 



pi. X. fig. 7. 

 1889. Barbatia pumila, Dennant, id. vol. xi. p. 60. 

 1893. Barbatia pumila, Tate and Dennant, id. vol. xvii. pt. 1, p. 224. 



Distinguished by the crenulations on the inside of the margin, 

 which are very conspicuous on the posterior portion ; dorsal and 

 ventral margins straight ; the radial ribs and concentric strise 

 produce granular thickenings at the points of intersection, the 

 ribs being much larger on the posterior slope than in the middle 

 of the valve ; umbones obtuse. 



Dimensions. — Height 5'5 mm. ; length 9 mm. 



Form, and Loc. — Eocene : Muddy Creek, Victoria. 



L. 4796. Eight valve, of the neanic stage of growth. 



Presented ly John Dennant, Esq. 



