58 ACM^A. 



Patelloida orbicularis Q. & G., Astrol. iii, p. 863, 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. PI. 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. — Teetura 

 jachsoniensis Angas, P. Z. S. 1867, p. 220. 



The smooth exterior and prominently rayed interior are the more 

 striking characters of this 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. 5i 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. (Rve.) 



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 Avhich /owr 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. 



