474 MOLLUSCA OF MAST HEAD REEF, QUEENSLAND, I., 



5mm. high, 9 '5 mm. long; and was dredged in 17-20 fathoms, off 

 Mast Head Island. 



Verticordia torrida, n.sp. 

 (Plate xxxvii., figs. 17, 18, 19.) 



Shell small, rather inflated, subrhomboidal. Right valve 

 exceeding and clasping the left. Umbo much incurved, on its 

 summit a small smooth sharply defined prodissoconch. Lunule 

 deeply excavate. Dorsal area flattened. Colour uniform clear 

 amber. Sculpture : the whole surface of the valve ornamented 

 with numerous faint radial riblets, separated by flat interspaces; 

 both riblets and interspaces crowded with sharp and very minute 

 grains. Interior highly nacreous, external radial sculpture 

 impressed between the pallial line and the margin. In the right 

 valve a massive cardinal under the umbo and a lateral under the 

 dorsal margin. Height 3 mm.; length 325 mm.; diameter of 

 conjoined valves, 1*1 mm. 



A few living specimens from 17-20 fathoms. 



Crassatellites janus, n.sp. 

 (Plate xxxviii., figs.29, 30, 31, 32.) 



Shell small, much compressed, subtrigonal, slightly inequi- 

 lateral. Colour buff to orange, with two or three interrupted 

 rays of chocolate and grey; the interior brown in the centre. 

 Sculpture: about sixteen concentric folds which become broader, 

 higher and more widely spaced as the shell grows. The inner 

 margin of the valve is smooth. The prodissoconch, worn away 

 in mature specimens, is shown (fig.32) in a shell 0*47 mm. in 

 height. Each prodissoconch rises from a rounded collar in a 

 double-peaked protuberance. Length 4 - 55 mm.; height 4-0 

 mm.; depth of single valve l - 5 mm. 



Numerous specimens in 17-20 fathoms. 



CUNA FLAVA, n.sp. 



(Plate xxxviii., fig.28.) 

 Shell small, solid, subtriangular, compressed. Colour mono- 

 chrome, usually orange, sometimes pink or purple. Sculpture: 



