54 ACM^EA. 



Length 13, breadth 10, alt. 11 mill. (.) 



Port Lincoln, S. Australia, on stones at low water ; Sow & Pigs 

 Reef, Port Jackson. 



Patelloida conoidea Q. & G., Astro!., p. 355, t. 71, f. 5-7. 

 Acmcea conoidea ANGAS, P. Z. S. 1865, p. 186. 



A. CALAMUS Crosse & Fischer. PI. 37, figs. 3, 4. 



Shell small, round-oval, erectly conical, apex in front of the 

 middle, slopes nearly straight. Surface sculptured with many acute, 

 unequal radiating riblets; dull pinkish-white, often with some ir- 

 regular dark brown markings. 



Inside white, lilac or pink-tinted, central area more opaque white 

 with a small brown spot in its depth ; border sparsely spotted with 

 brown. Length 10?, breadth 9, alt. 5 to 6 mill. 



Port Lincoln, on stones at low water ; Tasmania* 



Patella calamus C. & F. Journ. de Conchyl. 1864, p. 348 ; 1865, 

 t. 3, f. 7, 8. Acmcea calamus ANGAS, P. Z. S. 1865, p. 186. 



A. ALBA Tenison- Woods. PI. 42, figs. 76, 77, 78. 



Shell broad, oval, depressed, scabrous, thin, white, subshining; 

 apex sub-median, acute; radiated with numerous small, acute, un- 

 equal scaly-granose ribs, gathered into groups ; interstices delicately 

 and most closely undulose-striate. Inside shining-white, sometimes 

 rayed or clouded with pale-brown ; no spatula. Margin acute, 

 slightly undulating, elegantly fringed with a pale-tawny line. 



Length 26, width 22, alt. 7 mill. (T.-W.) 



North Coast of Tasmania. 



A. alba T.-W. Proc. Roy. Soc. Tasm. for 1876, p. 155, 1877. 



A white, silky species ; porcellanous inside and delicately mar- 

 gined with light-brown, not unlike the Chinese umbrella-shell, but. 

 smaller. The fine scabrous ribs are gathered sometimes into a bun- 

 dle, which thus forms a compound rib. It is very different from any 

 other southern form, and rare. ( T.-W.) 



The single specimen of this species before me does not agree very 

 well with the original description. This specimen is figured on my 

 plate. 



A. PETTERDI Tenison-Woods. Unfigured. 



Shell broadly ovate, tumid, depressed, apex acute and subniar- 

 ginal ; shining, dull white, very closely undula.tely striate with con- 

 centric growth lines and indistinctly radiated with wide, rude tawny 



