MOLLUSCA KAST OF CAPE BYRON. 



45 



third of the valve projects outward and upward into the mesial 

 sinus of the corresponding valve ; behind it is a broad shallow 

 sinus. 



Heii,'ht, 18 mm.; breath, 18 mm.; depth of pedicle valve, 6 mm. 



This species appears to be nearest to H. beecheri, Dall.,' from 

 313 fathoms, off Honolulu ; but, so far as I can judge, ours is a 

 broader, shallower shell, less flexed in front. 



Besides its occui'- 

 rence in 111 fathoms 

 east of Cape Byron, it 

 was taken by ]\Ir. 

 Halligan and myself 

 in 1 00 fathoms east of 

 Wollongong. From 

 tills parcel the type 

 was selected. Re- 

 cently it was again 

 procured by Mr. W. 

 F. Petterd and myself 

 in 250 fathoms twenty 

 three miles east of 

 Sydney. The species 

 appears to be common, since every haul on the margin of the con- 

 tinental shelf has yielded single and broken valves. No perfect 

 specimen has yet appt^ared. 



AVhile on the subject of the Brachiopoda, I might here notice 

 that Theculea maxilla, Hedley,* has lately been taken by Mr. D. 

 IMawson in the New Hebrides. 



"Fig:, 8. 



Hemithyris colurnus. 



PELECYPODA. 



Adacnarca squamea, sj). nov. 

 (Fig. 9). 



Shell minute, rounded-cordate, oblique inflated. Colour pale yel- 

 low. No epidermis apparent. External sculpture, faint, regular, 

 concentric growth lines. Prodissoconch depressed at the summit, 

 radially punctate, passing into the dissoconch without an elevated 

 margin, Hinge line straight, exactly divided by a small chon- 

 drophore, finely perpendicularly striated. The valve edge has 

 yentrally a broad, smooth, contact surface, like that of Limopsis ; 

 dorsally it carries on both anterior and posterior sides a series a 



s Dall—Proj. U.S. National Miisenni. xvi^., 1894, p. 717. 

 ^ Hedley— Aiiptr. Mup. Mem., iii.. ls()9, p 508. 



