BY C. HKDLEY. 54l 



and may likewise find an appropriate abiding place in the 

 Crassatellitidce. 



Enlarging Cyamiomactra by the addition of two Australian 

 species the genus may be thus reviewed : — 



C. iiroblematica, larger, compressed, no ribbing. 



G. mactroides, smaller, inflated, ribbed from end to end. 



C. communis, smaller, inequilateral, ovate, ribbed medially. 



C. mactroides Tate and May* was originally described from 

 Tasmania. Additional drawings of the shell and hinge (plate 

 xxxi., figs. 9, 10) are now tendered in support of the transfer- 

 ence from Cyamium to Cyamiomactra. As I recognise it, the 

 species varies so widely that on first acquaintance the extremes 

 appeared worthy of specific differentiation. In shape it is more 

 or less inflated, a very swollen form being expressed by Tate and 

 May's figure. In colour it is white or white tinged at end and 

 apex with brown, or all brown, or entirely bright pink. 

 Specimens from the northern extremity of its range are dwarfed. 



The following localities are known to me : — Eagle Hawk Neck, 

 Tasmania (Mrs. C. Hedley), Western Port, Victoria (J. H. 

 Gatliff), Wreck Bay, N.S.W. (self), off Port Kembla, N.S.W., in 

 63-75 fath. ("Thetis"), ocean beaches around Sydney (Miss L. 

 Parkes), Capricorn Group, Queensland (self). 



Cyamiomactra communis, n.sp. 



(Plate xxxi., figs. 11, 12,13.) 



Shell elongate-ovate, shallow, inequilateral, the posterior end 

 produced, the anterior rounded. Colour dorsally dark cinnamon- 

 brown, which gradually fades into translucent ice white, medially 

 a dozen narrow opaque rays, which do not represent a thickening 

 either within or without but are a denser substance contrasting 

 with the translucent ground. They fall short of the umbo. 

 Prodissoconch smooth, oval, rather flat and well defined. Sculp- 



* Trans. Roy. Soc. S.A., 1900, p. 102; these Proceedings, xxvi., p.433, 

 pi. xxvii., f.l03. 



