424 MOLLUSCA FROM THE HOPE ISLANDS, N. QUEENSLAND, 



are absent. Right anterior auricle ribbed by four spaced nodose 

 riblets, the posterior rayed by half a dozen tuberculate threads. 

 Ctenidium of five teeth. Interior smooth with plicate margins. 

 Height 20; length 20; depth of single valve 7 ram. 



Mr. A. Bavay, who kindly examined this species for me, con 

 aiders that it is a new species related to C. nux Reeve. G. smithi 

 Sowerby, is also akin. It was an abundant species off the Hope 

 Islands, and seems generally distributed in tropical Queensland, 

 for I took it, in 15 fathoms, off the Palm Islands, and, in 10 

 fathoms, off Mapoon. Mr. A. U. Henn collected it in anchor- 

 mud from lOJ fathoms off Cape Sidmouth. 



MoDiOLA AURicuLATA Krauss. 



Modiola auriculaia Krauss, Sudafrik. Moll. 1848, p. 20, PI. ii., 

 f.4; id., Smith, Zool. Coll. Alert, 1884,|p.508; id., Jukes Browne, 

 Proc. Malacol. Soc. vi. 1905, p.225; Lamy, Bull. Mus. d'Hist. Nat. 

 Paris, 1906, p.311. 



This mussel has not been before noted as Australian. Some 

 living specimens were gathered on the reef. 



CUNA PR^CALVA, n.sp. 



(Plate xxxvi., figs. 5-8.) 



Shell small, solid, rather inflated, equilateral, triangular- 

 cordate. Colour white. The dorsal margins straight, meeting 

 in a right angle, the ventral margin rounded. Sculpture : the 

 umbonal region is peculiarly smooth and flattened. Within it 

 the radial ribs are merely indicated, but without they assume 

 sudden prominence, and in each interstice another radial arises. 

 At the margin these ribs amount to about eighteen; they are 

 parted by rather broader, deep, steep-sided grooves, and on 

 their crests are spaced imbricating scales. The inner margin of 

 the valve is denticulated to correspond with the external sculp- 

 ture. The right margin develops a pseudo-lateral tooth, fitting 

 against a distant lateral tubercle within the left socket. The 

 socket itself is transversely striated. Height 1-95; length 2*05; 

 depth of single valve 075 mm. 



