50 ACM^A. 



Shell solid, conical, having seven prominent, angular radiating 

 ribs, projecting at the margin ; surface finely radiately striated when 

 not eroded ; variously marked with black blotches, usually v-shaped, 

 on a whitish ground. 



Inside white, the border gray marked with black or entirely 

 black ; central area with a patch of black or deep brown, covered 

 over with white in old specimens. Length 40, breadth 30, alt. 18 mill. 



Viti and Fiji Is ; Amboyna to Japan. 



P. saccharina L., Syst. Nat. x, p. 781, no. 660. REEVE, Conch. 

 Icon. f. 72. LISCHKE, Jap. Meeres-Conchyl. p. 113, 1869. 

 DUNKER, Index Moll. Mar. Jap. p. 155. Acmcea saccharina HAN- 

 LEY, in Wood's Index Test., 2d edit. p. 185, 1856. Collisella sac- 

 charina DALL, Am. Journ. Conch, vi, p. 259, 1. 15, f. 18 (dentition). 

 Patella lanx Rv., Conch. Icon. f. 82. 



The typical saccharina is best represented by the figures 60-62 of 

 PL 36. Sometimes smaller ribs are developed between the principal 

 ones, as in PI. 18, figs. 31, 32. Reeve's P. lanx (PI. 24, figs. 12, 13,) 

 is not a constant color variety. 



Var. STELLARIS Q. & G. PL 36, figs. 63, 64, 67, 68. 



Resembles saccharina in form. Central area of the inside dotted 

 with brown. 



New Ireland, etc. 



Patelloida stellaris Q. & G.. Voy. Astrol. Zool. iii, p. 356, t. 71, 

 f. 1-4, 1834 Patella stella LESSON, Voy. de la Coquille, Zool. ii, p. 

 421, 1830. P. octoradiataHuTTON. See below. 



A beautiful variety, of which numerous specimens from the col- 

 lection of Mr. John Ford, of Philadelphia are before me, (figs. 

 63, 64). 



The types of Quoy & Gaimard (figs. 67, 68,) differ somewhat 

 from the shells before me, in having the ribs more prolonged at the 

 margins, but agree in the number of principal rays, seven, and the 

 dotted spatula. Reeves P. stellaris is unlike the true stellaris in hav- 

 ing eight principal ribs and a solid brown spatula. See below. 



The name proposed by Lesson is anterior in date (1830), but be- 

 ing briefly described without a figure, is scarcely entitled to displace 

 the unmistakable diagnosis and good figures given by Quoy. 



Var. PERPLEX A Pilsbry. PL 36, figs. 69, 70, 71. 



Depressed, star-shaped, with four large rounded ribs behind, 

 three in front of the apex ; ribs and intervals closely striated. 

 White or creamy, with fine radiating reddish-brown lines. 



