140 I'ROCKEDINGS OF THE JIALACOLOGICAL SOCIKXy. 



to the length. The dorsal margin is regularly curved or arched on 

 both sides of the urabones. The liinge also offers some differences, 

 the teeth being rather more delicate, and the posterior lateral passes 

 into the lower edge of the chondrophore and not upwards towards 



the dorsal margin. The hinder adductor scar is ratlier smaller, 

 and the pallial sinus a little deeper. There is very little difference 

 in the external sculpture. 



6. Mactra (Spisula) amvtgdala, Crosse & Fischer, B.M. 



Mactra amygdala, Crosse & Fischer, Journ. de Conch., vol. xii, p. 349 ; 

 vol. xiii, p. 426, pi. xi, lig. 3; Weiukauff, p. 81, pi. xxviii, 



fig- 1- 

 Trigonella amygdala, Angas, Proc. Zool. Soc, 1865, p. 645. 



jjah. — Spencer's Gulf, South Australia (Angas). 



7. Mactka (Mactrinula) aspeksa, Sowerby. B.M. 



Jlacira aspersa, Sowerby, Tankerville Catalogue, Appendix, 1825, 

 p. 11 ; Reeve, pi. xiv, tig. 65 ; Weinkauff, p. 77, pi. xxvi, fig. 5. 

 M. tenera, Wood, Index test. Suppl., p. 4, pi. i, fig. 4. 

 Spisula tenera, Gray, Mag. Nat. Hist., vol. i, p. 373, 1837. 



ITab.— Torres Straits (Mus. Cuming), Attagor Islet, Torres Straits, 

 (J. B. Jukes in Brit. Mus.), Philippine Islands (Reeve and Hidalgo), 

 New Caledonia (Weinkauff), Van Diemen's Land (Wood), Queens- 

 land (Hedley). 



