216 



into the dorsal area. Dorsal area smooth. The median valves 

 each have one slit. The teeth under the microscope are 

 pectenated ; sinus broad and shallow. Inside colour creamy- 

 white with bluish patches. 



Girdle. — Clothed with imbricatins^ scales, apices sub-erect, 

 giving the girdle a rasp-like appearance. Scales pyramidal, 

 apices smooth, base ornamented with eight to ten vertical riblets. 



Measureme7it. — Length, 24 mm. ; breadth, 12 mm. 



Habitat. — Dredged in St. Vincent's Gulf, South Australia, by 

 Dr. Verco and W. D. Reed. Aldinga, by W. Kimber. 



Remarks. — It can easily be distinguished from allied species 

 by the strongly raised longitudinal tubercles in the lateral areas. 



2. Aeanthoehites eroeodilus, n. .^p. PI. 6., fig. 2. 



General Appearance. — Shell elongated, rounded, very broad in 

 proportion to the girdle. Side slope curved. Colour pale-olive- 

 green. 



Anterior Valve. — Strongly radially ribbed with five ribs. 

 Interspaces covered with more or less straight transverse rows 

 of squamose pustules. Two slits only discoverable in broken 

 specimen. 



Posterior Valve. — Mucro median distinctly beaked ; valve 

 divided into dorsal and pleural areas ; dorsal smooth and raised — 

 pinnatifid — and pleural similar to corresponding area in median 

 valves. Four slits. Sinus broad, 



Median Valves. — Lateral areas distinctly raised. Anterior 

 margin forming a strongl}' elevated diagonal rib, clothed with 

 irregular raised squamose pustules, having a confluent tendency. 

 Pleural area has a somewhat concave appearance, owing to the 

 raised character of lateral and dorsal areas. The whole covered 

 with triangular-shaped scales, which become very flat and large 

 as they approach the anterior margin. Pustules and triangular 

 scales are placed in longitudinal rows, continued through lateral 

 and pleural areas. Dorsal Areas. — Triangular, smooth, each 

 margin deeply notched with three to eight notches, prominently 

 beaked. Teeth, 1-1. 



Girdle. — Brown leathery, spongy, having on each side seven 

 and on anterior valve four tufts of short brownish spicules. 

 Microscopically mottled wit^ white, and densel}?- clothed with 

 minute, irregular, opaque sea es, «'hich give it a rough appearance. 



Measurements. — Length, 17 mm.; breadth, 8 mm.— in dried 

 specimen. 



Habitat. — Marino, South Australia ; discovered by Dr. Torr. 



Remarks. — Kemarkable for strongly raised diagonal rib, and 

 for its very coarse shagreening ; some of the scales being fully 

 half mm. across, and are microscopically striated. 



