58 ACM^EA. 



Patelloida orbicularis Q. & G., Astrol. iii, p. 363, t. 71, f. 31, 32 ; 

 var., f. 33, 35. 



A variety (pi. 37, figs. 95-97) from Amboyna is less rounded, 

 more oblong. 



A. JACKSONIENSIS Reeve. PL 42, figs. 71-75. 



Shell ovate, conical, the apex near the middle or somewhat in 

 front of it; surface smooth (or obsoletely radiately striated), dull, 

 usually corroded or incrusted ; color whitish rayed with brown. 



Inside conspicuously rayed with brown and white ; the central 

 area variously mottled with brown, or continuing the rays ; border 

 narrow, scarcely different from the rest of the inside layer in color. 



Length 19, breadth 15*, alt. 8 mill. 



Port Jackson, Australia, on rocks at low tide. 



Patella Jacksoniensis Rv., Conch. Icon. f. 127, 1855. Tectura 

 jacksoniensis ANGAS, P. Z. S. 1867, p. 220. 



The smooth exterior and prominently rayed interior are the more 

 striking characters of tnis species. The central area inside is vari- 

 ously clouded ; often the rays are continued into it. When the center 

 is entirely dark it is peculiar in shape ; see fig. 75. There is often 

 a tendency to form a white line just within the muscle-impression. 

 A depressed specimen measures, length 18, alt. 5 mill. 



Var. MIXTA Reeve. PI. 35, figs.. 32, 33. 



Shell ovate, rather thin, conoid, compressed at the sides ; apex 

 rather anterior, obsoletely decussately striated ; peculiarly mottled 

 with black and yellow, variegated in the interior. 



A thin, peculiar mottled shell, with somewhat the aspect of our 

 northern P. testudinalis. (JRve.) 



Port Phillip, Australia. 



P. mixta RVE., Conch. Icon., f. 129, 1855. 



Seems to be a synonym or variety of A. jacksoniensis. 

 A. CRUCIS Tenison-Woods. PI. 37, figs. 12, 13, 17, 18, 19. 



Shell oval, conical, apex somewhat in front of the middle ; slopes 

 nearly straight ; surface smooth, without radiating sculpture] lines of 

 growth fine, regular. Color a dead- white, with white apex, sur- 

 rounded by a small brown ring, from which four brown stripes, (in 

 the direction of major and minor axes of the shell) radiate. 



These stripes sometimes do not reach to the basal margin ; some- 

 times they split, and additional stripes appear in the intervals. 



